Gilera Nexus 500 Workshop Manual
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Gilera Nexus 500 Workshop Manual

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Table Of Contents
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Table of Contents

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WORKSHOP MANUAL
633309
Nexus 500

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Summary of Contents for Gilera Nexus 500

  • Page 1 WORKSHOP MANUAL 633309 Nexus 500...
  • Page 2 The descriptions and illustrations given in this publication are not binding. While the basic specifications as described and illustrated in this manual remain unchanged, PIAGGIO-GILERA reserves the right, at any time and without being required to update this publication beforehand, to make any changes to components, parts or accessories, which it considers necessary to improve the product or which are required for manufacturing or construction reasons.
  • Page 3 This workshop manual has been drawn up by Piaggio & C. Spa to be used by the workshops of Piaggio- Gilera dealers. This manual is addressed to Piaggio service mechanics who are supposed to have a basic knowledge of mechanics principles and of vehicle fixing techniques and procedures. Any important changes made to the vehicles or to specific fixing operations will be promptly reported by updates to this manual.
  • Page 5 INDEX OF TOPICS CHAR HARACTERISTICS TOOL OOLING MAIN AINTENANCE ELE SYS LECTRICAL SYSTEM ENG VE NGINE FROM VEHICLE NGINE INJEC NJECTION SUSP USPENSIONS BRAK SYS RAKING SYSTEM COOL SYS OOLING SYSTEM CHAS HASSIS PRE DE DELIVERY TIME...
  • Page 6 INDEX OF TOPICS CHAR HARACTERISTICS...

  • Page 7: Safety Rules

    Nexus 500 Characteristics This section describes the general specifications of the vehicle. Rules This section describes general safety rules for any maintenance operations performed on the vehicle. Safety rules • Should it be necessary to keep the engine running while servicing, make sure that the area or room is well ventilated, and use special exhaust fans, if required.

  • Page 8: Vehicle Identification

    Nexus 500 Characteristics Vehicle identification Characteristic Engine prefix: M351M Characteristic Chassis prefix: ZAPM35100 Dimensions and mass WEIGHT Specification Desc./Quantity Dry weight 199 kg Width 765 mm Length 2090 mm Wheel base 1515 mm Saddle height 780 mm Height 1045 mm...
  • Page 9 Nexus 500 Characteristics Specification Desc./Quantity Valve clearance: intake 0.15 mm (when cold) Valve clearance: discharge 0.15 mm (when cold) Valve clearance adjustment By threaded adjuster on the rockers Engine idle speed 1500 ± 50 rpm Air filter Dry paper filter.

  • Page 10: Wheels And Tyres

    Nexus 500 Characteristics Specification Desc./Quantity Rear suspension Type "Power drive": Shock absorber (with double- acting helicoidal spring and adjustment of the spring preload in 7 positions) mounted in horizon- tal position, connected to a connecting rod pivoted to a strut with variable length.

  • Page 11: Tightening Torques

    Nexus 500 Characteristics Specification Desc./Quantity Tyre pressure (cold) rear 2.3 bar (2.5 bar with passenger) N.B. CHECK AND ADJUST TYRE PRESSURE WITH TYRES AT AMBIENT TEMPERATURE. ADJUST PRESSURE ACCORDING TO THE WEIGHT OF RIDER AND ACCESSORIES. CAUTION IT IS MANDATORY TO ADOPT EXCLUSIVELY "S" CLASS TYRES, WHICH GUARANTEE COR- RECT VEHICLE PERFORMANCE AT THE DIFFERENT SCOOTER SPEEDS.

  • Page 12: Table Of Contents

    Nexus 500 Characteristics Name Torque in Nm Clamping of connection rod supporting strut and shock ab- 73 - 80 sorber to frame Clamping of rear strut support to hub cover 20 - 25 Lower strut clamping 30 - 35 Rear strut support clamping to crankcase...

  • Page 13: Assembly Clearances

    Nexus 500 Characteristics FLYWHEEL COVER Name Torque in Nm Chain guide sliding block retain plate fastening screws 3 ÷ 4 Flywheel fixing nut 115 - 125 Stator retainers 8 - 10 Blow-by recovery duct fixing screws 3 - 4 Screw fixing freewheel to flywheel 13 ÷...
  • Page 14 Nexus 500 Characteristics (Values in mm) HEIGHT AT WHICH THE DIAMETER SHOULD BE MEASURED Specification Desc./Quantity 10 mm 43 mm CATEGORIES OF COUPLING Name Initials Cylinder Piston Play on fitting Cylinder Piston 91.990 - 91.997 91.954 - 91.961 0.029 - 0.043 Cylinder Piston 91.997 - 92.004...
  • Page 15 Nexus 500 Characteristics This selection is useful to keep the difference between the working distance of the gears and their distance without clearance at a given value in order to avoid abnormal noise. TYPE A Specification Desc./Quantity Centre to centre distance of the gears without clearance 76.937 ÷...
  • Page 16 Nexus 500 Characteristics AXIAL CLEARANCE BETWEEN CRANKSHAFT AND CONNECTING ROD Name Description Dimensions Initials Quantity Transmission-side 0.8 ± 0.025 D= 0.20 - 0.40 shoulder Transmission-side half- 19.6 + 0.050 D= 0.20 - 0.40 shaft Connecting rod 22 0.10-0.15 D= 0.20 - 0.40 Flywheel-side shoulder 13 ±...
  • Page 17 Nexus 500 Characteristics BASE GASKET MUST BE THICKER, THE MORE THE PLANE FORMED BY THE PISTON TOP PROTRUDES FROM THE PLANE FORMED BY THE CYLINDER HEAD. ON THE OTHER HAND, THE MORE THE PISTON TOP IS RECESSED INTO THE CYLINDER TOP PLANE, THE SMALLER THE GASKET THICKNESS.
  • Page 18 INDEX OF TOPICS TOOL OOLING...
  • Page 19 Nexus 500 Tooling TOOLS Stores code Description 001330Y Tool for fitting steering seats 001467Y002 Driver for OD 73 mm bearing 001467Y006 Pliers to extract 20 mm bearings 001467Y007 Driver for OD 54-mm bearings 001467Y008 Pliers to extract 17 mm ø bearings 001467Y014 Pliers to extract ø...
  • Page 20 Nexus 500 Tooling Stores code Description 001467Y031 Bell 001467Y034 Pliers to extract ø 15-mm bearings 001467Y035 Belle for OD 47-mm bearings 002465Y Pliers for circlips 006029Y Punch for fitting fifth wheel seat on steer- ing tube 020004Y Punch for removing fifth wheels from...
  • Page 21 Nexus 500 Tooling Stores code Description 020055Y Wrench for steering tube ring nut 020150Y Air heater support 020151Y Air heater 020193Y Oil pressure gauge 020201Y Spacer bushing driving tube 020262Y Crankcase splitting strip 020306Y Punch for assembling valve seal rings...
  • Page 22 Nexus 500 Tooling Stores code Description 020329Y MityVac vacuum-operated pump 020330Y Stroboscopic light to check timing 020331Y Digital multimeter 020333Y Single battery charger 020334Y Multiple battery charger TOOL - 22...
  • Page 23 Nexus 500 Tooling Stores code Description 020335Y Magnetic support for dial gauge 020357Y 32 x 35 mm adaptor 020358Y 37x40-mm adaptor 020359Y 42x47-mm adaptor 020360Y Adaptor 52 x 55 mm 020364Y 25-mm guide 020376Y Adaptor handle 020382Y012 bush (valve removing tool)
  • Page 24 Nexus 500 Tooling Stores code Description 020412Y 15 mm guide 020424Y Driven pulley roller casing fitting punch 020431Y Valve oil seal extractor 020434Y Oil pressure control fitting 020439Y 17 mm guide TOOL - 24...
  • Page 25 Nexus 500 Tooling Stores code Description 020444Y Tool for fitting/ removing the driven pulley clutch 020456Y Ø 24 mm adaptor 020458Y Puller for lower bearing on steering tube 020459Y Punch for fitting bearing on steering tube 020460Y Scooter diagnosis and tester...
  • Page 26 Nexus 500 Tooling Stores code Description 020468Y Piston fitting band 020469Y Reprogramming kit for scooter diagnosis tester 020470Y Pin retainers installation tool 020471Y Pin for countershaft timing 020472Y Flywheel lock wrench TOOL - 26...
  • Page 27 Nexus 500 Tooling Stores code Description 020474Y Driving pulley lock wrench 020475Y Piston position checking tool 020476Y Stud bolt set 020478Y Punch for driven pulley roller casing 020479Y Countershaft lock wrench 020480Y Petrol pressure check set TOOL - 27...
  • Page 28 Nexus 500 Tooling Stores code Description 020481Y Control unit interface wiring 020482Y Engine support 020483Y 30 mm guide 020512Y Piston fitting fork 020527Y Engine support base 020604Y011 Fitting adapter 020565Y Flywheel lock calliper spanner TOOL - 28...
  • Page 29 Nexus 500 Tooling Stores code Description 020623Y Pre-service gas extraction set 020625Y Kit for sampling gas from the exhaust manifold 494929Y Exhaust fumes analyser TOOL - 29...
  • Page 30 INDEX OF TOPICS MAIN AINTENANCE...

  • Page 31: Maintenance Chart

    Nexus 500 Maintenance Maintenance chart Adequate maintenance is fundamental to ensuring long-lasting, optimum operation and performance of your vehicle. To this end, a series of checks and maintenance operations (at the owner's expense) have been sug- gested, which are included in the summary table on the following page. Any minor faults should be reported without delay to an Authorised Service Centre or Dealer without waiting until the next scheduled service to solve it.
  • Page 32 Nexus 500 Maintenance AFTER 6,000 KM OR 12 MONTHS Action Engine oil - replacement Hub oil - level check Spark plug / electrode gap - check Air filter - cleaning Engine oil - change Valve clearance - check Base vent - check...
  • Page 33 Nexus 500 Maintenance AFTER 24,000 KM 255' Action Engine oil - replacement Hub oil - change Spark plug / electrode gap - replacement Air filter - clean Engine oil - change Fuel filter - check Carburetion - check/adjust Seals/injection system hoses - visual check...
  • Page 34 Nexus 500 Maintenance Action Brake control levers - greasing Brake fluid hoses - replacement Transmission elements - lubrication Brake fluid level - check Safety locks - check Suspensions - check Electrical system and battery - check Headlight - adjustment Tyre inflation and wear - Check...

  • Page 35: Spark Plug

    Nexus 500 Maintenance Action Electrical system and battery - check Headlight - adjustment Tyre inflation and wear - Check Vehicle and brake test - road test Transmission elements - lubrication Spark plug Check and replacement CAUTION THE SPARK PLUG MUST BE REMOVED WITH COLD EN- GINE.
  • Page 36 Nexus 500 Maintenance Check Check the oil in the rear hub. Characteristic Rear hub oil Capacity approximately 250 cc To check the rear hub oil level, proceed as follows: - Park the scooter on flat ground resting on its centre stand.
  • Page 37 Nexus 500 Maintenance - Unscrew the oil drainage plug and drain out all the oil. - Tighten the drainage plug with its gasket and re- fill. - Tighten the oil filler plug. Characteristic Rear hub oil Capacity approximately 250 cc...

  • Page 38: Engine Oil

    Nexus 500 Maintenance - Replace the air filter and reassemble the various components, reversing the removal procedure. - An inspection and possible cleaning (with com- pressed air) of the air filter is scheduled every 6000 km in any case. - The air jet must be directed from the inside to the outside of the filter (i.e.

  • Page 39: Engine Oil Filter

    Nexus 500 Maintenance Check This operation must be carried out with the engine cold and following the procedure below: 1) Rest the vehicle on the central stand and on a flat ground. 2) Unscrew the cap/dipstick "A", dry it with a clean cloth and reinsert it, screwing it thoroughly.

  • Page 40: Engine Oil Drainage Plug

    Nexus 500 Maintenance - Remove and clean the mesh pre-filter of the drain cap with compressed air. - Use a belt spanner for filters to remove cartridge filter "C". - Make sure the pre-filter and drain cap O-rings are in good condition.

  • Page 41: Checking The Valve Clearance

    Nexus 500 Maintenance Oil pressure warning light Warning light (low oil pressure) The vehicle is equipped with a warning light on the instrument panel that lights up when the key is turned to the «ON» position. However, this light should switch off once the engine has been star- ted.
  • Page 42 Nexus 500 Maintenance CAUTION THIS OPERATION MUST BE CARRIED OUT WHEN THE ENGINE IS COLD. - Remove the water pump cover as indicated in the figure by loosening the 6 retaining screws. - Proceeding as described in chapter "Engine", partially drain the system and overhaul the pump.

  • Page 43: Braking System

    Nexus 500 Maintenance Braking system Level check - Rest the scooter on a flat ground and on the cen- tral stand. - Remove the brake pump cover as shown in the figure. - Check the brake fluid level by the special indica- tor located on the pump, as shown in the figure.

  • Page 44: Headlight Adjustment

    Nexus 500 Maintenance - Remove the tank cap by loosening its two screws, remove the gasket and top up the level, using only the prescribed fluid without exceeding the maximum level. CAUTION AVOID CONTACT OF THE BRAKE FLUID WITH YOUR EYES, SKIN, AND CLOTHING.
  • Page 45 Nexus 500 Maintenance - Otherwise, adjust the right headlight by the screw shown in the figure, which can be accessed by re- moving the front shield connecting member. N.B. THE ABOVE PROCEDURE COMPLIES WITH THE EURO- PEAN STANDARDS REGARDING MAXIMUM AND MINI- MUM HEIGHT OF LIGHT BEAMS.
  • Page 46 INDEX OF TOPICS ELE SYS LECTRICAL SYSTEM...
  • Page 47 Nexus 500 Electrical system ELECTRICAL SYSTEM Specification Desc./Quantity Left headlight for sidelight N° 1 12V-55W bulb Front left direction indicator 1 bulb 12V - 10W Rear brake stop button Left electric control Front fuse holder terminal board Fuse Fuse 7,5 A...
  • Page 48 Nexus 500 Electrical system Specification Desc./Quantity Instrument panel Horn Electric fan Wheel RPM sensor Electric control management device Immobilizer decoder Electronic injection control unit Saddle opening receiver Diode unit Electric fan remote control switch Control unit remote control switch Engine stop switch...
  • Page 49 Nexus 500 Electrical system Overturn sensor In order to access the overturn sensor, remove the central union. During assembly, observe the installation direction shown in the figure. H.V. coil In order to access the high-voltage coil, remove the left-hand side fairing.
  • Page 50 Nexus 500 Electrical system Electronic control unit ECU In order to access the immobilizer control unit, re- move the upper shield back plate. In order to access the connector, remove the wind- shield with the respective support and the metal plate holding the control unit ECU, decoder and saddle opener remote control.
  • Page 51 Nexus 500 Electrical system Voltage regulator To access the voltage regulator. Conceptual diagrams Ignition ELE SYS - 51...
  • Page 52 Nexus 500 Electrical system IGNITION Specification Desc./Quantity Instrument panel HV coil Stoplight switches Start up button Fuse 7,5 A Control unit remote control switch Stop light Fuse Diode Engine stop remote control switch Starter motor Engine stop indicator Remote starter switch...
  • Page 53 Nexus 500 Electrical system Headlights and automatic starter section LIGHT AND FLASHING LIGHT BULBS SECTION Specification Desc./Quantity Hazard indicator light management electronics Hazard indicator N° 4 flashing light bulbs Fuse 7,5 A Light switch Upper beam Key switch contacts Fuse...
  • Page 54 Nexus 500 Electrical system Specification Desc./Quantity Number plate light N° 2 front taillight bulbs Taillight indicator Key switch contacts Fuse Fuse Voltage regulator Fuse 7,5 A Fuse 7,5 A Key switch contacts Indicators switch Hazard switches Electric control management device...
  • Page 55 Nexus 500 Electrical system Specification Desc./Quantity Engine stop indicator Engine stop switch Stand switch Battery 12V - 14 Ah Voltage regulator Magneto flywheel Level indicators and enable signals section SAFETY SWITCHES AND LEVEL INDICATOR SECTION Specification Desc./Quantity Tachometer Instrument panel...
  • Page 56 Nexus 500 Electrical system Specification Desc./Quantity Horn Electric fan motor Fuse Electronic injection control unit Electric fan remote control switch Diode Engine stop switch Stand switch Engine stop indicator Key switch contacts Key switch contacts Fuse 7.5 A Fuse Battery...
  • Page 57 Nexus 500 Electrical system WARNING BEFORE CARRYING OUT THE CHECK, MAKE SURE THAT THE BATTERY IS IN GOOD WORK- ING ORDER. 1) Place the vehicle on its centre stand 2) With the battery correctly connected to the circuit, place the tester terminals between the battery terminals..
  • Page 58 Nexus 500 Electrical system Fuses The electric system is equipped with: - Six fuses «A» located inside the right side. - 5 fuses «B» in the un- dersaddle compart- ment. - A 30A fuse (main fuse), next to the bat- tery on the left side;...
  • Page 59 Nexus 500 Electrical system The tables show the po- sition and the charac- teristics of the fuses present in the vehicle FUSE HOLDER A (HELMET COMPART- MENT) Specification Desc./Quantity Not used Number plate light - Posi- tion lights - Instrument unit...
  • Page 60 Nexus 500 Electrical system BELT: This lamp should come on every 12000 km. • Pressing "MODE" and "ODO/SET" at the same time while inserting the key to "ON" for more than 3 seconds, the "BELT" icon will start to flash.
  • Page 61 Nexus 500 Electrical system • Digital instrument The digital section provides the displays of: - Injection warning light (amber) - Low fuel warning light (amber) - Oil pressure warning light (red) - Turn signal warning light (green) - Immobilizer LED (red)
  • Page 62 Nexus 500 Electrical system 6. Battery voltage The battery symbol appears Pressing button "MODE" for longer than 3 seconds returns you to function "1" of the sequence (average speed). - The display also contains the symbols: BELT: Indicates the need to replace the transmission...
  • Page 63 Nexus 500 Electrical system Set the "DATE" using the "CLOCK". If the button "CLOCK" is pressed for longer than 3 seconds, the figures showing the days start to flash. Set the day with the «ODO/SET» button. Press the "CLOCK" button again; the numbers showing the months start to flash.
  • Page 64 Nexus 500 Electrical system The battery should always be kept clean, especially on its top side, and the terminals should be coated with Vaseline. CAUTION NEVER USE FUSES WITH A CAPACITY HIGHER THAN THE RECOMMENDED CAPACITY. USING A FUSE OF UNSUITABLE RATING MAY SERIOUSLY DAMAGE THE VEHICLE OR EVEN CAUSE A FIRE.
  • Page 65 Nexus 500 Electrical system 2 Inspect visually 3 The float must be freed Checking the electrolyte level The electrolyte level must be checked frequently and must reach the upper level. Only use distilled water, to restore this level. If it is necessary to add water too frequently, check the vehicle's electrical system: the battery works overcharged and is subject to quick wear.
  • Page 66 Nexus 500 Electrical system CHARGE THE BATTERY BEFORE USE TO ENSURE OPTIMUM PERFORMANCE. FAILURE TO CHARGE THE BATTERY ADEQUATELY BEFORE BEING PUT INTO OPERATION WILL LEAD TO A PREMATURE FAILURE OF THE BATTERY. Phonic wheel - Ensure that the tone wheel is correctly installed on the scooter and connected to the electrical system.
  • Page 67 Nexus 500 Electrical system Layout of the system-side connectors and the con- nectors on the electronic control unit. Specification Desc./Quantity Throttle potentiometer power supply +5 V Rpm indicator / consumption counter Engine temperature 86 electric fan remote control switch Stepper motor...
  • Page 68 Nexus 500 Electrical system Seat opening receiver RECEIVER CONTROL UNIT FOR SADDLE OPENER Specification Desc./Quantity Radio aerial Actuator positive output 1 Reset / Input clearing Battery positive (Not connected) Live positive lead Ground lead (Not connected) (Not connected) Selection input CH1 / CH3...
  • Page 69 Nexus 500 Electrical system Engine rev. sensor REV SENSOR Specification Desc./Quantity Male Female Shielding Dashboard The instrument panel is provided with two connec- tors ("A" with 20 pins and "B" with 12 pins) shown in the figure. Connector "A" KEY: 1.
  • Page 70 20. Emergency warning flashers Connector "B" KEY: 1. Rpm indicator (D) 2. Rpm indicator (B) 3. - 4. - 5. ICP/ID "NEXUS 500" 6. ICP/ID "NEXUS 250" 7. Rpm indicator (C) 8. Rpm indicator (A) 9. - 10. - 11. - 12.

  • Page 71: Battery Replacement

    Nexus 500 Electrical system This remote control is supplied together with the keys and at the manufacturing stage, it has been programmed to work together with the ECU that control the opening device. If the remote control is lost, a new one can be requested and reprogram it by resetting the ECU memory and following the same steps as per programming the immobilizer system in the keys.
  • Page 72 Nexus 500 Electrical system 2. Turn the key to ON, press the button on the remote control, release the button, turn the key back to OFF from the ON position, all within four seconds. 3. Wait 1 to 8 seconds 4.
  • Page 73 INDEX OF TOPICS ENG VE NGINE FROM VEHICLE...
  • Page 74 Nexus 500 Engine from vehicle Exhaust assy. Removal - Loosen the two mountings of the exhaust mani- fold at the cylinder head. Remove the screw indicated in the photograph. - Loosen the screw shown in the figure so as to loosen the muffler strap and remove the whole muffler.
  • Page 75 Nexus 500 Engine from vehicle - Carry out the removal operations but in reverse order and respect the locking torques indicated in the «Specifications» Chapter. CAUTION PAY PARTICULAR ATTENTION TO POSITIONING THE THROTTLE CONTROL TRANSMISSION PROPERLY. Check that there is a small clearance when the valve is in abutment against the set screw.
  • Page 76 INDEX OF TOPICS NGINE...

  • Page 77: Transmission Cover

    Nexus 500 Engine This section describes the operations to be carried out on the engine and the tools to be used. Automatic transmission Transmission cover - Using a screwdriver, remove the driven pulley axle cover near the bottom of the cap.
  • Page 78 Nexus 500 Engine - Remove the four M8 screws. - Remove the transmission cover. - Check that the bearing rotates freely, otherwise replace it. - Loosen the 4 fastening screws - Extract the outside plastic transmission cover. Air duct - Remove the transmission cover.
  • Page 79 Nexus 500 Engine Air duct filter - Remove the external air conveyor. - Unscrew the 2 fastening screws shown in the fig- ure to remove the conveyor filter. Removing the driven pulley shaft bearing - Remove the transmission cover. - Remove the Seeger ring.
  • Page 80 Nexus 500 Engine Refitting the driven pulley shaft bearing - Heat the transmission cover interior using the heat gun. N.B. BE CAREFUL NOT TO OVERHEAT THE COVER AS THIS WOULD DAMAGE THE OUTSIDE PAINTED SURFACE. Specific tooling 020151Y Air heater - Place the bearing onto the special tool with a little grease to prevent it from coming out.

  • Page 81: Removing The Driven Pulley

    Nexus 500 Engine - Check that the roller does not show signs of wear and that it turns freely. - Loosen the retaining bolt using a 13 mm spanner. - Remove the complete roller with bearing. N.B. IF THE ROLLER DOES NOT ROTATE FREELY, REPLACE THE COMPLETE ROLLER.

  • Page 82: Removing The Clutch

    Nexus 500 Engine Removing the clutch - To remove the clutch with the driven pulley it is necessary to use the special tool; - Arrange the tool with the mean pins screwed in position "E" on the inside; - Install the driven pulley unit onto the tool inserting the pins into the ventilation holes;...
  • Page 83 Nexus 500 Engine Removing the driven half-pulley bearing - Check that the bushing is free from wear and damage; otherwise replace the fixed driven half- pulley. - Remove the lock ring using pliers. - Using the special tool inserted through the roller bearing, pull out the ball bearing.
  • Page 84 Nexus 500 Engine Inspecting the driven fixed half-pulley - Check that the belt contact surface is free from wear. - Measure the outer diameter of the pulley bushing. Characteristic Minimum admissible diameter 49.91 mm Standard diameter: 50.00 -0.015 -0.035 mm...

  • Page 85: Refitting The Driven Pulley

    Nexus 500 Engine Specific tooling 020478Y Punch for driven pulley roller casing 001467Y002 Driver for OD 73 mm bearing - Install a new ball bearing using the special tool. Specific tooling 020376Y Adaptor handle 020477Y Adaptor 37 mm 020363Y 20 mm guide - Insert the Seeger lock ring.
  • Page 86 Nexus 500 Engine Soap-based lithium grease containing NLGI 2 Molybdenum disulphide; ISO-L-XBCHB2, DIN KF2K-20 Inspecting the clutch spring - Measure the length of the spring, while it is re- laxed. Characteristic Standard length: 125.5 mm Admissible limit after use: 120 mm - Check the thickness of the clutch mass friction material.

  • Page 87: Clutch Ring Nut

    Nexus 500 Engine Refitting the clutch Bell assembly - Install the bell and the spacer. - Prepare the special tool as for removal; - Preassemble the driven pulley unit with the drive belt according to its direction of rotation; - Insert the driven pulley unit, the spring with sheath and clutch into the tool.

  • Page 88: Removing The Driving Pulley

    Nexus 500 Engine Refitting the driven pulley - Install the driven pulley assembly with belt. Drive-belt - Check that the driving belt is not damaged. - Check the width of the belt. Characteristic Minimum width: 25 mm Standard width: 26.2 mm...
  • Page 89 Nexus 500 Engine - First install the lock ring of the special tool onto the pulley so that the splines are completely en- gaged. - Then, insert the tool so as to insert the stud bolts on the ring into the holes obtained onto the tool itself.
  • Page 90 Nexus 500 Engine - Measure the pulley sliding bushing outside di- ameter shown in the figure. Characteristic Minimum admissible diameter Ø 29.95 mm Standard diameter: Ø 29.959 mm - Check that the rollers are not damaged or worn. Characteristic Minimum admissible diameter Ø...
  • Page 91 Nexus 500 Engine Refitting the driving pulley Installing the roller container - Install the spacer with the internal chamfer facing towards the inside. - Position the rollers on the half-pulley as shown in the figure. - The closed side must rest on the inside thrust face of the roller container.
  • Page 92 Nexus 500 Engine Installing the fixed driving half-pulley - Insert the spacer. - Install the fixed driving half-pulley and check that it is in contact with the spacer and with the guide bushing of the moving driving pulley. - Remove the flat washer and the spring washer as shown in the figure.

  • Page 93: Driving Pulley Nut

    Nexus 500 Engine - Turn the central pulley nut to horizontally align the holes and install the special tool. N.B. CHECK THAT THE STOP WRENCH TOOL IS EASILY IN- SERTED INTO THE PULLEY AND IN THE ENGINE CRANK- CASE. Specific tooling...
  • Page 94 Nexus 500 Engine - Lock the 7 M6 retainers. Locking torques (N*m) M6 retainer 11 ÷ 13 - Insert the washers on the driven pulley shaft. N.B. INSERT THE SMALLER WASHER FIRST, THEN THE LARGER ONE. - Insert the flanged nut.
  • Page 95 Nexus 500 Engine - Install the outside plastic transmission cover. - Tighten the 4 fastening screws to the prescribed torque. Locking torques (N*m) External transmission cover screws 7 ÷ 9 End gear Removing the hub cover - Drain the rear hub oil through the oil drainage cap located under the engine.
  • Page 96 Nexus 500 Engine Removing the hub bearings - Check all bearings (wear, clearance and noise). In case of anomalies, proceed as follows. To remove the gear shaft bearing on the engine crankcase, use the following parts. Specific tooling 001467Y014 Pliers to extract ø 15-mm bearings 001467Y034 Pliers to extract ø...
  • Page 97 Nexus 500 Engine - Support the hub cover using the column kit. - Pull out the bearing using the special tool. Specific tooling 020476Y Stud bolt set 020376Y Adaptor handle 020477Y Adaptor 37 mm 020483Y 30 mm guide - Remove the oil guard using a screwdriver.
  • Page 98 Nexus 500 Engine Inspecting the hub shaft - Check that the 3 shafts exhibit no wear or defor- mation on the grooved surfaces, at the bearings and at the oil guards. - In case of faults, replace the damaged parts.
  • Page 99 Nexus 500 Engine - Insert the driven pulley shaft bearing until it abuts against the bottom of the seat using the special tool. N.B. PLACE IT WITH THE BALLS FACING THE HUB (THIS AP- PLIES TO BEARINGS WITH PLASTIC CAGE).
  • Page 100 Nexus 500 Engine - Insert the pulley shaft oil guard on the transmis- sion side. Refitting the hub cover bearings - Heat the bearing seats on the cover using the heat gun. - Support the hub cover using the column kit.
  • Page 101 Nexus 500 Engine - Replace the snap ring - Support the hub cover using the column kit. - Insert the wheel shaft oil guard with the sealing lip facing the inside of the cover. - Place the oil guard flush with the crankcase.
  • Page 102 Nexus 500 Engine - Position the 7 set screws, tighten them to the prescribed torque, being careful of the position of the bands holding the vent tube, and the position of the 3 shortest screws as indicated in the figure.
  • Page 103 Nexus 500 Engine - Remove the pre-filter. - Remove the oil filter using a filter tape or shaped cup wrench. - Loosen the 14 fastening screws. - Remove the flywheel cover with the relevant gas- ket and the cooling system sleeve support.

  • Page 104: Removing The Stator

    Nexus 500 Engine Removing the flywheel cover components - Loosen the six mounting screws and remove the water pump cover. - Remove the by-pass and the relevant spring. - Remove the oil pump seal. Removing the stator - Remove the two retaining screws and the cable guide bracket.
  • Page 105 Nexus 500 Engine - Loosen the two retaining screws and remove the reed valve support with bulkhead. - Remove the blow-by reed valve with the relevant sealing gasket. - Unscrew the fastening screw and remove the gas outlet union with the relevant O-ring.
  • Page 106 Nexus 500 Engine - Extract the shaft with the relevant abutment washer. - Remove the sealing ring. - Remove the ceramic ring and the relevant gas- ket. - Remove the sealing ring for the pump shaft lu- brication using a suitably shaped tool.
  • Page 107 Nexus 500 Engine - Remove the engine oil filling cap/dipstick and the check hole cover for the distribution timing. - Remove the minimum oil pressure sensor. Inspecting the cover components - Install a new oil filter, lubricate the gasket, screw on and finally tighten to the prescribed torque.
  • Page 108 Nexus 500 Engine - Check the condition of the stator and of the re- spective cable harness. - Check the continuity between the 3 phases. N.B. VALUES ARE STATED AT AMBIENT TEMPERATURE. A CHECK WITH THE STATOR AT OPERATING TEMPERA- TURE MAY RESULT IN VALUES HIGHER THAN THOSE STATED.
  • Page 109 Nexus 500 Engine - Check that the mounting surface of the crankcase is not worn or deformed. - Check that the by-pass valve seat, the torque limiter and the water pump shaft are free from wear. Characteristic By-pass housing hole diameter: 13.9 mm...
  • Page 110 Nexus 500 Engine - Install the wiring guide bracket tightening the 2 screws to the prescribed torque. Locking torques (N*m) Stator cable harness guide bracket screws 3 - 4 - Temporarily install the distribution timing check hole cover and the engine oil filling cap/bar.
  • Page 111 Nexus 500 Engine - Oil feeding duct at the water pump shaft connec- tion. - Pump drainage duct. - Oil pressure sensor feeding duct. - Oil vapour decantation chamber ENG - 111...
  • Page 112 Nexus 500 Engine - Reinstall the blow-by reed valve using a new sealing gasket. - Reinstall the support with head and tighten the screws to the prescribed torque. Locking torques (N*m) Supporting screws with bulkhead 0.3 - 0.4 - Install a new sealing ring for the pump shaft using...
  • Page 113 Nexus 500 Engine - Screw the impeller and tighten to the prescribed torque. Locking torques (N*m) Water pump impeller 4 ÷ 5 Refitting the flywheel cover - Lubricate the intermediate gear seat with torque limiter on the flywheel cover. - Align the water pump movement sensor with a reference and install the flywheel cover as descri- bed in the Flywheel cover chapter.
  • Page 114 Nexus 500 Engine - Repeat the alignment for the water pump crank- shaft using the same reference point on the en- gine. N.B. THIS PREPARATION IS USEFUL PARTICULARLY IN THE EVENT OF REPAIRS WITH THE WATER PUMP COVER IN- STALLED.
  • Page 115 Nexus 500 Engine START-UP REMOTE CONTROL SWITCH Specification Desc./Quantity Type SEALED Maximum load 150 A continuous STARTER TRANSMISSION Specification Desc./Quantity Ring gear and freewheel coaxial to the flywheel. Intermediate gear with built-in torque limiter. The starter system has a transmission between the motor armature and engine shaft equipped with freewheel coaxial to the flywheel and torque limiter on the intermediate shaft.
  • Page 116 Nexus 500 Engine Select the "PARAMETERS" function. Start the engine (so that it cannot move) long enough to measure the rpm and starter absorption. N.B. THE DECLARED RPM VALUE IS THAT INDICATED BY THE TESTER, THE RPM READING IS NOT THE REAL ONE, BUT IS VALID FOR DIAGNOSTIC PURPOSES.
  • Page 117 Nexus 500 Engine YES go to 12 NO go to 13 9 - High trailing speed Low electrical absorption The engine turns too freely, check the compression end pressure. If the values are not correct proceed as follows. 10 - The starter motor works properly.
  • Page 118 Nexus 500 Engine - Unscrew the 3 fastening screws and remove the chain guide sliding block retain plate and the start- up rim. - Align the holes obtained on the flywheel with the crankcase housing to allow the introduction of the special tool.
  • Page 119 Nexus 500 Engine - Loosen the magneto flywheel fastening nut. - Remove the special tool and the fastening nut. - Remove the washer. - Insert the nut again so as to slightly uncover the shaft and free the space that was occupied by the washer.
  • Page 120 Nexus 500 Engine - Remove the extractor. - Remove the nut and extract the flywheel with the start-up rim. - Remove the crankshaft key. - To remove the start-up rim from the freewheel it is necessary to turn it clockwise and pull it out.
  • Page 121 Nexus 500 Engine - Extract the intermediate gear provided with tor- que limiter. Inspecting the flywheel components - Check the integrity of the magnets. - Check that the magnet support cage is free from deformation or cracks. - Check that the flywheel splines exhibit no loos- ening.
  • Page 122 Nexus 500 Engine IF THE FAULTS DISCOVERED AFFECT THE HUB, REPLACE THE STARTER RING GEAR AND FREEWHEEL. IF ONLY THE BUSHING IS WORN, IT IS POSSIBLE TO REPLACE ONLY THE COMPLETE START- UP RIM. IN THAT CASE, CHECK ALSO THE DIAMETER AND THE SURFACE OF THE CONNEC- TION ON THE CRANKSHAFT.
  • Page 123 Nexus 500 Engine - Degrease the threading of the holes in the free wheel and the clamping screws. - Apply the recommended product to the end of the screws. Recommended products Loctite 243 Medium strength threadlock Loctite 243 medium-strength threadlock...
  • Page 124 Nexus 500 Engine - Insert the intermediate gear with torque limiter - Lubricate the inside bushing and the starter ring gear hub surface. - Install the start-up rim on the flywheel turning it clockwise and inserting at the same time.
  • Page 125 Nexus 500 Engine - Insert washer and nut on the crankshaft. - Tighten thoroughly the guide bushing of the fly- wheel lock tool and loosen by 1/4 turn. N.B. FAILURE TO OBSERVE THIS RULE CAUSES THE LOCK- ING OF THE GUIDE ON THE FLYWHEEL.
  • Page 126 Nexus 500 Engine - Tighten the flywheel lock nut to the prescribed torque. Locking torques (N*m) Flywheel fixing nut 115 - 125 - Install the chain guide retain plate tightening the 3 screws to the prescribed torque. N.B. BEFORE TIGHTENING THE SCREWS, MOVE THE START-...
  • Page 127 Nexus 500 Engine - Remove the flywheel cover, the flywheel and the torque limiter. Removing the intake manifold - Remove the 3 mounting screws. - Remove the intake manifold unit. Removing the rocker-arms cover - Loosen the 6 special screws with stop and the relevant rubber gaskets.
  • Page 128 Nexus 500 Engine Removing the timing system drive - Turn the engine to close the intake valves, i.e., moving the reference on the tone wheel to the top, as shown in the figure. - Remove the central screw and the valve lifting device mass stop bell using the special tool.
  • Page 129 Nexus 500 Engine - Loosen the central screw on the tensioner first. - Unscrew the 2 fastening screws and remove the tensioner with relevant gasket. Remove the inside hexagon screw and the coun- terweight as shown in the figure. - Remove the timing belt rim from the camshaft.
  • Page 130 Nexus 500 Engine - Remove the engine revolution timing sensor and relevant O-ring by loosening the fastening screw and removing the mounting band from the special hole obtained on the head gasket. N.B. TO CHECK THIS COMPONENT, SEE THE INJECTION CHAPTER.

  • Page 131: Removing The Cylinder Head

    Nexus 500 Engine Removing the cylinder head - Remove the spark plug. - Remove the cooling system outlet sleeve with thermostat. - Remove the coolant temperature sensor. N.B. THE SENSOR CONTROLS BOTH INJECTION AND THE AN- ALOGUE INSTRUMENT ON THE PANEL. TO CHECK THIS COMPONENT, SEE THE INJECTION CHAPTER.

  • Page 132: Removing The Valves

    Nexus 500 Engine - Loosen the 4 head-cylinder fastening nuts in 2 or 3 times and in a crossed sequence. - Remove the head, the 2 centring dowels, the gasket and the lower chain guide sliding block. N.B. DO NOT REMOVE THE DOWELS IF THEY ARE FORCED INTO THEIR SEAT.
  • Page 133 Nexus 500 Engine - Remove the spring supports. N.B. BLOW THE SEATS WITH COMPRESSED AIR TO FACILI- TATE THE SPRING SUPPORT REMOVAL. Removing the cylinder - piston assy. - Remove the timing chain. - Loosen the fastening screw and remove the spacer and the tightening sliding block.

  • Page 134: Inspecting The Small End

    Nexus 500 Engine - Remove the piston sealing rings and the oil scra- per. CAUTION NOTE THE ASSEMBLY POSITIONS OF THE LININGS TO PREVENT INVERTING THE POSITION IN CASE OF REUSE. N.B. BE CAREFUL NOT TO DAMAGE THE SEALING RINGS DURING REMOVAL.

  • Page 135: Inspecting The Piston

    Nexus 500 Engine - Calculate the piston pin coupling clearance. N.B. THE PIN HOUSINGS HAVE 2 LUBRICATION CHANNELS. FOR THIS REASON, MEASUREMENT MUST BE MADE AC- CORDING TO THE PISTON AXIS. Characteristic Standard clearance: 0.001 ÷ 0.010 mm Inspecting the piston - Measure the outside diameter of the piston, per- pendicular to the gudgeon pin axis.
  • Page 136 Nexus 500 Engine - Carefully clean the seal housings. - Measure the coupling clearance between the seal rings and the grooves using suitable sensors, as shown in the diagram. - If the clearance is greater than that indicated in the table, replace the piston.

  • Page 137: Removing The Piston

    Nexus 500 Engine Removing the piston - Install piston and wrist pin onto the connecting rod, aligning the piston arrow the arrow facing to- wards the exhaust. - Insert the locking ring into the special tool, with the opening in the position indicated on the tool.
  • Page 138 Nexus 500 Engine Choosing the gasket - Provisionally fit the piston into the cylinder, without any base gasket. - Install a comparator on the special tool using the short union, as shown in the figure. Specific tooling 020475Y Piston position checking tool - Using an abutment plane, reset the comparator with a preload of a few millimetres.
  • Page 139 Nexus 500 Engine + 0.10 ÷ + 0.185 Gasket thickness 3 0.8 ± 0.05 Refitting the piston rings - Place the scraper ring spring on the piston. - Install the scraper ring keeping the opening op- posed to the spring junction and with the writing "top"...

  • Page 140: Inspecting The Cylinder Head

    Nexus 500 Engine Inspecting the cylinder head - Using a trued bar and a feeler thickness gauge check that the cylinder head surface is not worn or distorted. Characteristic Maximum allowable run-out: 0.1 mm - In case of irregularities, replace the head.
  • Page 141 Nexus 500 Engine - Remove the centre screw with the washer and the tensioner spring. Check that the one-way mechanism is not worn. - Check the condition of the tensioner spring. - If examples of wear are found, replace the whole assembly.
  • Page 142 Nexus 500 Engine Inspecting the valve housings - Clean the valve seats of any carbon residues. - Using the Prussian blue, check the width of the impression on the valve seat "V". - Measure the inside diameter of each valve guide.
  • Page 143 Nexus 500 Engine - Check the deviation of the valve stem by resting it on a "V" shaped abutment and measuring the extent of the deformation with a comparator. Characteristic Limit values admitted: 0.1 mm - Check the concentricity of the valve head by ar- ranging a comparator at right angle relative to the valve head and rotate it on a "V"...
  • Page 144 Nexus 500 Engine STANDARD VALVE LENGTH Specification Desc./Quantity Inlet: 95.0 ± 0.3 mm Outlet: 94.2 ± 0.3 mm - Check that there are no signs of wear on the surface of contact with the articulated register terminal. - If the checks above give no failures, you can use the same valves.
  • Page 145 Nexus 500 Engine - Measure the unloaded spring length. Characteristic Standard length: 44.4 mm Admissible limit after use: 42.4 mm Refitting the valves - Place the valve spring support washers on the head. - Alternately insert the 4 oil guards using the spe- cial tool.
  • Page 146 Nexus 500 Engine MINIMUM ADMISSIBLE DIAMETER Specification Desc./Quantity Bearing A Ø: 41.910 mm Bearing B diameter: 19.940 mm -Using a gauge, measure the cam height. STANDARD HEIGHT Specification Desc./Quantity Intake 33.988 mm Exhaust: 33.417 mm ADMISSIBLE LIMITS Specification Desc./Quantity Intake 33.740 mm...
  • Page 147 Nexus 500 Engine - Check that the valve lifting spring has not yielded. - Replace any defective or worn components. - Check that the rocking lever pins exhibit no scores or wear. Characteristic Standard diameter: 13 - 0.010 -0.018 mm - Measure the inside diameter of each rocking lever.

  • Page 148: Exhaust / Intake Head Fixing Nuts

    Nexus 500 Engine - The head gasket is made of steel and has a standard thickness. - Check that the head lubrication channel is per- fectly clean. Clean with compressed air jets, if required. - Insert the head. - Lubricate the stud bolts and the 4 fixing stud bolts.

  • Page 149: Coolant Temperature Sensor:

    Nexus 500 Engine - Tighten the 3 side screws to the prescribed tor- que. Locking torques (N*m) Head fixing screws 10 - 12 - Install the coolant temperature sensor with the washer and tighten to the prescribed torque. CAUTION FAILURE TO OBSERVE THE TIGHTENING TORQUE CAN DAMAGE THE SENSOR.

  • Page 150: Camshaft Retaining Bracket Screws:

    Nexus 500 Engine - Clean the camshaft by blowing with little com- pressed air jets, especially the retaining plate housing. - Lubricate the 2 shafts. - Insert the camshaft into the head with the cams opposite the rocking levers. - Remove any LOCTITE residues from the screws fixing the camshaft retaining bracket using a brush.
  • Page 151 Nexus 500 Engine - Insert the wheel speed sensor on the camshaft keeping the stroke reference visible. - Install the engine revolution timing sensor using a new O-Ring, orientating it as shown in the figure. Tighten the 2 fastening screws to the prescribed torque.
  • Page 152 Nexus 500 Engine - Align the wheel speed sensor references with the head as shown in the figure. - Keeping the belt slightly pulled, turn the crank- shaft using the driving pulley to make the reference on the magnet support collimate with that on the flywheel cover.
  • Page 153 Nexus 500 Engine - Remove the central screw. - Install the valve lifting mass being careful to the proper positioning of the travel end ring. - Lubricate the mass and de-compressor control pin. - Install the return spring and load it by about 3/4 turn.

  • Page 154: Valve Lifter Mass Stop Bell Fixing Screws

    Nexus 500 Engine - Check that the decompression mass is free and that it is pulled by the spring. Locking torques (N*m) Valve lifter mass stop bell fixing screws 30 - 35 - Place the engine with the valve clearance adjustment timing references aligned with the head.
  • Page 155 Nexus 500 Engine Proceed as follows: - Remove the outside transmission cover as de- scribed in the automatic transmission chapter. - Remove the TDC reference inspection cap be- tween flywheel and crankcase cover. See the fly- wheel cover chapter. - By the driving pulley, turn the engine to find the alignment of the references to identify the TDC.
  • Page 156 Nexus 500 Engine - Replace the inspection cap on the flywheel side. - Connect the diagnostic tester. - Start the engine. - Select the «parameter» function in this menu. - Select the stroboscopic light command in the tra- ditional four-stroke engine position (1 spark 2 revs).
  • Page 157 Nexus 500 Engine - Place the tightener cursor in the rest position, keeping the retain tab pressed. - Install a new tightener on the cylinder using a new gasket. - Tighten the two fastening screws to the prescri- bed torque.

  • Page 158: Tappet Cover Fixing Screws

    Nexus 500 Engine - Tighten the two screws indicated in the figure with «1» and «2» to limit the reciprocal sliding of the cover surface with the head surface. - Tighten the remaining 4 screws in a crossed se- quence (3, 4, 5, 6).
  • Page 159 Nexus 500 Engine Crankcase - crankshaft - Remove the outside and inside transmission cov- er and the complete driving pulley as described in "Automatic transmission". - Remove the flywheel cover with the cooling sys- tem sleeves, as described in the "Flywheel cover"...
  • Page 160 Nexus 500 Engine - Before opening the crankcase, check the crank- shaft axial clearance. For this purpose, use a plate (e.g. the special tool) and a support with special tool comparator. Specific tooling 020262Y Crankcase splitting strip 020335Y Magnetic support for dial gauge...
  • Page 161 Nexus 500 Engine - Remove the 14 crankcase coupling screws. N.B. THE FASTENING SCREWS ARE OF 3 DIFFERENT LENGTHS. NOTE THEIR CORRECT POSITION. - Split the crankcases while keeping the crankshaft inserted on the flywheel side half-crankcase. - Remove the coupling gasket.
  • Page 162 Nexus 500 Engine Removing the oil pump and countershaft con- trol gear. - To remove the control gear, loosen the 4 fasten- ing screws. Remove the gear only if actually required. CAUTION THE SCREWS HAVE A COUNTERSUNK HEAD AND THEIR THREADING IS LOCKED BY LOCTITE.
  • Page 163 Nexus 500 Engine Replacing the countershaft bearings - Check that the bearings are free from irregular noise or clearance. If it does, replace it. Flywheel-side half-crankcase - Remove the inside Seeger ring. - Upturn the half-crankcase. - Remove the bearing from the flywheel side half- crankcase using the special tool and a mallet.
  • Page 164 Nexus 500 Engine - Insert a new bearing on the special tool after greasing the guide seat. - Install the new bearing on the half-crankcase us- ing the special tool. N.B. IF A BEARING WITH PLASTIC CAGE IS USED, KEEP THE BALLS VISIBLE FROM THE CRANKCASE INTERNAL SIDE.
  • Page 165 Nexus 500 Engine 020439Y 17 mm guide Inspecting the crankshaft components - Check the axial clearance on the connecting rod. Characteristic Standard clearance: 0.20 ÷ 0.40 mm - Check the connecting rod diametrical clearance. Characteristic Standard clearance: 0.046 ÷ 0.076 mm...
  • Page 166 Nexus 500 Engine - Check that shim adjustment is free from scratches. N.B. IN CASE OF NEW UTILISATION, MAINTAIN THE FIRST FITTING POSITION. Specific tooling 020074Y Support base for checking crankshaft alignment - If the crankshaft - crankcase axial clearance is higher than the standard value and the crankshaft exhibits no irregularity, the problem is caused by wear or by a wrong machining on the engine crankcase.
  • Page 167 Nexus 500 Engine - In case of failures, replace the crankshaft. N.B. MAIN BEARINGS CANNOT BE MODIFIED. The connecting rod cannot be replaced. To check the connecting rod small end diameter, see chapter "Thermal group and timing system". - When cleaning the crankshaft, be careful to prevent any impurity from entering into the shaft lubrication hole.
  • Page 168 Nexus 500 Engine N.B. THE JET IS FED THROUGH THE MAIN BUSHINGS. PROP- ER OPERATION OF THIS COMPONENT IMPROVES THE PISTON TOP COOLING. CLOGGING HAS EFFECTS THAT ARE DIFFICULT TO DETECT (PISTON TEMPERATURE IN- CREASE). FAILURE OR LEAK CAN CONSIDERABLY DE- CREASE THE MAIN BUSHING AND CONNECTING ROD LUBRICATION PRESSURE.
  • Page 169 Nexus 500 Engine Inspecting the crankshaft plain bearings - To obtain a good bushing lubrication it is neces- sary to have both an optimal lubricating pressure (4 bar) and a good oil flow rate; the bushings must be correctly positioned so as not to obstruct the oil supply channels.
  • Page 170 Nexus 500 Engine Coupling chart COUPLING THE SEMI-SHAFTS WITH THE SEMI-CHASSIS AND BUSHES Name Description Dimensions Initials Quantity Half-shaft category 1 - Spare crankcase set-up Bushing category B FC1 - Dis. CM1033015001 Half-shaft category 2 - Spare crankcase set-up Bushing category C FC1 - Dis.

  • Page 171: Gear Mounting On Crankshaft Screws

    Nexus 500 Engine - Before installing the gear on the crankshaft, care- fully clean the two matching surfaces removing any residues of LOCTITE from the holes using a brush. Blow with compressed air and degrease the mounting holes on both surfaces to make the new LOCTITE grip.

  • Page 172: Bulkhead Screws For Oil Pump Housing Cover

    Nexus 500 Engine - Insert the crankshaft on the pin and into the bush- ing. - Before inserting thoroughly, make the oil pump gear align with the control gear. - Insert thoroughly and remove the special tool. N.B. WHEN INSERTING THE SHAFT ON THE HALF-CRANKCASE, BE CAREFUL NOT TO DAMAGE THE MAIN BEARING WITH THE THREADED TANG OF THE CRANKSHAFT AND WITH THE TIM- ING CONTROL TOOTHED PINION.
  • Page 173 Nexus 500 Engine - Insert the gasket on the flywheel side half-crank- case. - Lubricate the main bearing on the transmission side half-crankcase. - Couple the 2 half-crankcases being careful not to damage the bushing on the transmis- sion side half-crankcase with the threaded tang of the crankshaft.
  • Page 174 Nexus 500 Engine - Install the flywheel with start-up control as de- scribed in the "Flywheel and start-up" chapter. - Install the flywheel cover with the cooling system sleeves, as described in the "Flywheel cover chap- ter". - Install the complete driving pulley, the transmis-...

  • Page 175: Head Lubrication Control Jet

    Nexus 500 Engine OIL PUMP Specification Desc./Quantity Type Trochoidal Rotor washers 8 mm Assembly clearances Lobe ends 0.05-0.008 mm External rotor radial clearance 0.05- 0.12 mm Rotor axial clearance 0.025 - 0.065 mm BY-PASS Specification Desc./Quantity Type with piston Plunger diameter 13.9 - 0.039 -0.057 mm...
  • Page 176 Nexus 500 Engine Conceptual diagrams PRINCIPLE DIAGRAM Specification Desc./Quantity Camshaft Cylinder-head plane Cylinder-crankcase plane Water pump impeller Minimum oil pressure sensor Oil filter cartridge To the oil sump By-pass valve Oil pump Mesh pre-filter Crankshaft Connecting rod General characteristics The lubrication system is divided into two sections:...
  • Page 177 Nexus 500 Engine The pump is controlled by means of a piston by-pass calibrated to 4 bar. This is located before the cartridge filter and both are installed on the flywheel cover, so that the seal of the filter is subject to the pressure of the circuit.
  • Page 178 Nexus 500 Engine 3 Check the actual oil pressure. AHEAD - go to 4 4 - Remove the switch and fit the special tool with the relevant gasket. Specific tooling 020193Y Oil pressure gauge 020434Y Oil pressure control fitting - Remove the dipstick with the oil filling cap and insert a cap fitted with the temperature probe supplied with the special tool.

  • Page 179: Oil Pressure Check

    Nexus 500 Engine 8 - If pressure lower than 1.3 ÷ 1.5 bar is measured. AHEAD go to 9 9 - Replace the oil filter and repeat the pressure check with oil at 80°C. YES go to 10 NO go to 13 10 - The failure was fixed.
  • Page 180 Nexus 500 Engine 020434Y Oil pressure control fitting AHEAD go to 3 3 - Check the system pressure with cold engine and medium - high speed. Standard pressure < 6 bar YES go to 4 NO go to 5 4 - Replace the damaged components.
  • Page 181 Nexus 500 Engine - Remove the oil pump complete with the gearing by loosening the 2 retaining screws through the eyes machined in the gearing proper. - Remove the gasket. - Remove the two screws and the oil pump cover.
  • Page 182 Nexus 500 Engine - Remove and wash the rotors thoroughly with pet- rol and compressed air. - Extract the shaft with its gear and check that it is in good working order and free from wear. - Reassemble the rotors in the pump body, keep-...
  • Page 183 Nexus 500 Engine - Check the rotor axial clearance using a rectified bar as reference plane, as shown in the figure. Characteristic Limit values admitted: 0.1 mm Inspection - For tests on the oil pump, see the "Lubrication" chapter. Refitting - Make sure the gasket is in the correct position.
  • Page 184 Nexus 500 Engine Failure to observe the tightening torque may alter the coupling clearance of the rotors with the pump body. Locking torques (N*m) Screws fixing oil pump to crankcase 5 - 6 - Insert the countershaft with gearing into the fly- wheel-side half-crankcase.
  • Page 185 Nexus 500 Engine Oil pump cover screws 0.7 ÷ 0.9 ENG - 185...
  • Page 186 INDEX OF TOPICS INJEC NJECTION...
  • Page 187 Nexus 500 Injection TERMINALS CONDITIONS STANDARD 5 - 23 Switch in position "ON" Battery voltage Switch on "RUN" Side stand raised Electric fan off CIRCUIT LAYOUT Specification Desc./Quantity electronic control unit Electric fan Fuse Key switch Electric fan remote control switch...
  • Page 188 Nexus 500 Injection - Coolant level in the expansion tank - bleeding of the inlet hose to the engine - Bleeding of the outlet from the head - Function of the thermostat - Function of the pump For these checks, see chapter "Cooling system".
  • Page 189 Nexus 500 Injection 9 - Replace the remote control switch YES go to 8 10 - Connect the special tool between the control unit and the system. Do not connect the electronic control unit YES go to 11 11 - Check for positive battery voltage at pin 85 of the remote control switch connector.
  • Page 190 Nexus 500 Injection If the fault continues, replace the electronic control unit. Make sure the entire exhaust system is sealed. Remove the intake cap on the exhaust pipe, connect the dissipater and the extension pipe. Warm-up the engine and use an exhaust analyser to check the carburation of the idle speed, if neces- sary, restore the correct setting using a scooter Tester, see «Adjusting idle carburation».
  • Page 191 Nexus 500 Injection - that air filter is clean - that throttle body is clean - intake system for sealing - exhaust system for sealing - valve clearance - fuel filter - Fuel pressure N.B. IDLE SPEED IS OBTAINED BY PRE-CALIBRATING THE THROTTLE BODY AND THE ACTIVITY OF THE STEPPER.
  • Page 192 Nexus 500 Injection 8 - Activate the exhaust fumes analyser and check the following conditions are present: - CO = 1.25±0.25% - CO2 = 14.50±1% YES go to 9 NO go to 10 9 - The adjustment is correct. 10 - If a different CO value is read, adjust the idle injection timing.
  • Page 193 Nexus 500 Injection 14 - After having modifying a trimmer value, wait until the CO value becomes steady. In case of incorrect adjustment, press OK to store the value in the control unit memory. YES go to 15 15 - Select «PARAMETERS» and «ECU DATA»...
  • Page 194 Nexus 500 Injection In any case, check the CO value again. EMS injection system This vehicle is fitted with an integrated injection and ignition system. Injection is indirect in the manifold through an electro-injector. Injection and ignition are timed on the 4-stroke cycle using a tonne wheel pivoted on the camshaft control and a reluctance variation sensor.
  • Page 195 Nexus 500 Injection Of course, this cannot happen when the rpm-timing signal is missing, or when the failure involves the control circuits: - Fuel pump - HV coil - Injector The control unit is provided with a self-diagnosis system connected to an indicator light in the in- strument panel.
  • Page 196 Nexus 500 Injection The EMS control unit power supply is further con- trolled by the emergency switch and by the side stand switch, that is to provide further safety for the scooter. Precautions 1. Before fixing any part of the injection system, check to see if there are any registered faults. Do not disconnect the battery before checking for faults.
  • Page 197 Nexus 500 Injection 14. Before reconnecting the quick couplers of the power supply system, check that the terminals are perfectly clean. Terminals setup Layout of the system-side connectors and the connectors on the electronic control unit. ELECTRONIC CONTROL UNIT SIDE...
  • Page 198 Nexus 500 Injection Specification Desc./Quantity Continuous power supply (positive) IMMOBILIZER DECODER Specification Desc./Quantity Immobilizer LED control (negative) Base power supply (positive) Negative Electronic control unit EMS (serial) Continuous power supply (positive) Immobilizer aerial EMS circuit diagram Specification Desc./Quantity Electric fan remote control switch...
  • Page 199 Nexus 500 Injection Specification Desc./Quantity HV coil Fuel pump Instrument panel Injector Fluid temperature sensor Air temperature sensor Throttle potentiometer Stepper motor Stepper motor Electronic control unit EMS (serial) Immobilizer aerial Decoder EMS diagnostic socket Stroke revolution sensor Stand switch...
  • Page 200 Nexus 500 Injection Possible Cause Operation H.V. coil Injector revolution timing sensor Air temperature Coolant temperature. Atmospheric pressure Start up engine speed Starter motor and remote control Battery Ground connections End of compression pressure End of compression pressure Power to the spark plug...
  • Page 201 Nexus 500 Injection Engine does not rev down ENGINE DOES NOT RETURN TO THE IDLING SPEED/IDLING SPEED TOO HIGH Possible Cause Operation Presence of faults detected by the self diagnosis Pump relay H.V. coil Injector revolution timing sensor Air temperature Coolant temperature.
  • Page 202 Nexus 500 Injection Engine revs irregularly IRREGULAR PROGRESS OF THE ENGINE WITH VALVE SLIGHTLY OPEN Possible Cause Operation Presence of faults detected by the self diagnosis Pump relay H.V. coil Injector revolution timing sensor Air temperature Coolant temperature. Atmospheric pressure...
  • Page 203 Nexus 500 Injection Engine knocking PRESENCE OF KNOCKING (OVERHEAD KNOCKING) Possible Cause Operation Presence of faults detected by the self diagnosis Pump relay H.V. coil Injector revolution timing sensor Air temperature Coolant temperature. Atmospheric pressure Ignition efficiency Spark plug Parameter reliability...
  • Page 204 Nexus 500 Injection 1 - Check whether the immobiliser system LED in- dicates that the switch is in position "ON" and that the deterrent flashing is on. YES go to 2 NO go to 7 2 - The decoder is properly programmed.
  • Page 205 Nexus 500 Injection Terminal no. 4= battery negative YES go to 11 NO go to 13 Specific tooling 020481Y Control unit interface wiring 11 - Decoder with proper base power supply. Use the special tool to check the control unit power...
  • Page 206 Nexus 500 Injection 3 - Continuous power supplies are regular 4 - Check the working order of the fuse no. 4 and 5 located in the fuse holder on the right side. YES go to 5 NO go to 6 5 - Place the special tool between control unit and injection system.
  • Page 207 Nexus 500 Injection 9 - Control unit with proper continuous power sup- ply. 10 - If only one component is not powered check the relevant connector. If the problem involves both the decoder and CPU check the continuity of the decoder CPU power supply line.
  • Page 208 Nexus 500 Injection Diagnostic circuit * CONNECTOR FOR DIAGNOSTIC TESTER A = INJECTION CONTROL UNIT Connect the diagnostic tester. Specific tooling 020460Y Scooter diagnosis and tester If the diagnostic tester displays «No reply from the control unit», disconnect the continuous power supply for 10 seconds and switch to «ON»...
  • Page 209 Nexus 500 Injection 5 - Check the following conditions: PIN 1 diagnostic socket - PIN 10 control unit = continuity PIN 2 diagnostic socket - PIN 23 control unit = continuity with earth PIN 3 diagnostic socket - PIN 9 control unit = con- tinuity 10 - 23 = insulation (>1 MΩ)
  • Page 210 Nexus 500 Injection Specification Desc./Quantity - Side stand raised - Switch to "RUN" STANDARD VALUES : O V TERMINAL: 15 - 23 CONDITIONS: AFTER THE CHECK - Switch set to "ON" - Side stand raised - Switch to "RUN" STANDARD VALUES : Battery voltage The injection telltale light is controlled upon every switching to "ON"...
  • Page 211 Nexus 500 Injection The injection ECU manages the negative of the light. The light must go off after the initial check. The light goes on again when the ECU self-diagnosis detects a fault. When the fault disappears the light goes back off, however, the related operating tests need to be carried out. The light can go on whether the engine is able to run or not.
  • Page 212 Nexus 500 Injection - Injector and relevant circuit - HV coil and relevant circuit - Stepper and relevant circuit - Pump relay circuit - Electric fan relay circuit - RAM memory - ROM memory - EEPROM - Microprocessor - Signals panel (stroke - revolution signal - unsteady cycle) Underlined failures cause the engine to stop.
  • Page 213 Nexus 500 Injection The pipes are crossed and fixed to the intake manifold to prevent wear of the quick unions connected to the T union for the injector. N.B. BEFORE WORKING ON THE FUEL SUPPLY SYSTEM, CAREFULLY CLEAN THE PARTS TO PREVENT DAMAGING THE FAST-RELEASE COUPLING SEAL OR TO PREVENT DIRT GETTING INTO THE DUCTS.
  • Page 214 Nexus 500 Injection Specification Desc./Quantity Injector Electronic injection control unit Main remote control switch Engine stop switch Stand switch Removing the injector N.B. ONLY REMOVE THE INJECTOR FROM THE MANIFOLD IN THE EVENT OF A PROVEN DEFECT. OPERATING TEST OF THE INJECTOR MUST BE PERFORMED WITH THE INJECTOR INSTALLED ON THE MANIFOLD (SEE "INJECTION").

  • Page 215: Injector Fixing Screw

    Nexus 500 Injection Refitting the injector Carefully check to make sure the components are clean. - Fit new O-rings and grease them. - Apply the recommended product to the set screws and tighten to the prescribed torque. Recommended products Loctite 243 Medium strength threadlock...
  • Page 216 Nexus 500 Injection - Make sure the seal rims on the coupling surfaces between the manifold-throttle body and manifold- head are in good condition. CAUTION IF AIR GETS IN IT CAN JEOPARDISE THE OPERATION OF THE INJECTION SYSTEM, ESPECIALLY WHEN THE EN- GINE IS IDLING.
  • Page 217 Nexus 500 Injection injection warning light turns on or further errors or wrong parameters are present, it is necessary to carry out the relevant controls indicated in the manual. In such a case, there is a real fault evidently. Refitting the butterfly valve...
  • Page 218 Nexus 500 Injection 6 - Try to start up. Select the function "ERRORS" in the menu. Check whether there are any failures. YES go to 7 YES go to 8 NO go to 28 7 - Pump control relay circuit failure.
  • Page 219 Nexus 500 Injection 16 - Replace the control unit. 17 - Check the presence of voltage (+ batt.) be- tween pin 86 of the pump remote control switch and pin 23 of the control unit. Fix the wiring, if re- quired.
  • Page 220 Nexus 500 Injection 23 - Restore the wiring insulation and replace the fuse. 24 - Check the ground insulation of the primary winding of the HV coil and of the injector coil. YES, go to 25 25 - Check the pump winding resistance: approx.
  • Page 221 Nexus 500 Injection Circuit leak test Before performing the checks concerning the sys- tem pressure, it is necessary to carefully clean all feeding system components. To perform the inspections it is necessary to use the special tooling kit for fuel pressure check.
  • Page 222 Nexus 500 Injection The system pressure check must be carried out, for practical reasons, by connecting on the pump side. Connect the manometer to the outlet duct (RHS) and the extension tube to the inlet duct (LHS). CAUTION BEFORE REASSEMBLING CHECK THE TOOL DUCTS ARE CLEAN.
  • Page 223 Nexus 500 Injection 4 - The pressure regulator is efficient. 5 - Pressure too high Check that the return duct is not clogged or squashed YES go to 6 NO go to 7 6 - Replace the pressure regulator. 7 - Pressure regulation too low Start the pump rotation again.
  • Page 224 Nexus 500 Injection 2 - Let bleed for a few seconds. Make sure that there are no leaks. Using pliers with flat and long tips, temporarily clamp the return duct by the extension of the spe- cial tool with pump power supply voltage higher than 12 V, check the system maximum pressure.
  • Page 225 Nexus 500 Injection 10 - There occur trend variations YES go to 11 NO go to 13 11 - Repeat the test clamping the pipe of the spe- cial tool in the portion between the branch and the injector. Check whether the pressure decreases with the same trend as the system when free.
  • Page 226 Nexus 500 Injection 17 - Introduce the return pipe into a graduated container. Using the diagnostic tester, start the fuel pump for 10 seconds. Make sure that the power supply voltage is more than 12V. Measure the amount of fuel delivered.
  • Page 227 Nexus 500 Injection Pump consumption check The pump power consumption may vary according - Power supply voltage - Pump running-in - Regulation pressure - Delivery filter cleaning To check the current consumption, proceed as fol- lows - Disconnect the pump remote control switch con- nector.
  • Page 228 Nexus 500 Injection Pump bracket overhaul To remove the pump support from the tank, pro- ceed as follows: - Disconnect the electric connector. - Start the engine and wait for the spontaneous stop. - Clean the tank and the pump support (wash and blow with compressed air, if necessary).
  • Page 229 Nexus 500 Injection Pass the wires through the hole found between fil- ter and pressure regulator. - Disconnect and extract the wires - Using a screwdriver on the retain tab as shown in the figure, extract the level indicator from the...
  • Page 230 Nexus 500 Injection - Lubricate the O-rings and repeat the operations in the reverse order for reassembly. (3) Fuel pump - Note the position of the power supply wires on the support pos 1 = positive (red) pos 4 = negative (black)
  • Page 231 Nexus 500 Injection - Remove the filter coupling pipe - Remove the pump with annular support and pre- filter. - If the pump requires replacement, remove the pre-filter and the annular support. - For reassembly, perform the removal operations but in the reverse order using a new clamp for the delivery pipe and a new pump mounting washer.
  • Page 232 Nexus 500 Injection Pump bracket installation - Before reassembling, carefully check that the tank is clean. In case of dirt or water, remove the tank. - Install the sealing gasket on the pump support. - Introduce the pump into the tank being careful not to deform the level indicator arm.
  • Page 233 Nexus 500 Injection CIRCUIT LAYOUT Specification Desc./Quantity Electronic control unit Injector HV coil Pump Control unit remote control switch Fuse 10 A 1 - Connect the diagnostic tester. Select the menu on the "ACTIVE DIAGNOSIS" function. Select the "INJECTOR" function.
  • Page 234 Nexus 500 Injection 5 - No injector openings detected. The injection tester displays «test failed». YES go to 9 NO go to 6 6 - No injector openings detected. The injection tester displays «test successful». YES go to 8 7 - The injector control circuit is efficient. Perform the injector hydraulic check.
  • Page 235 Nexus 500 Injection 15 - Arrange a multimeter with positive prod on pin 13 and negative prod on pin 23. Set the switch to "ON" with switch to "RUN" and side stand raised. Check the presence of battery voltage during the fuel pump timing.
  • Page 236 Nexus 500 Injection Inspecting the injector hydraulics To check the injector it is advisable to remove the intake manifold along with throttle body and injec- tor. The injector should be removed from the manifold only if necessary. For these operations, see the "thermal group and timing system"...

  • Page 237: Troubleshooting

    Nexus 500 Injection 3 - Perform the injector sealing test. Dry the injector outlet with a blast of compressed air. Activate the fuel pump. Wait for one minute, making sure there are no leaks coming from the injector. Slight oozing is normal.

  • Page 238: System Components

    Nexus 500 Injection Specification Desc./Quantity 3. Fuel supply - Faulty fuel pump - Dirty fuel filter 4. Ignition system - Faulty spark plug - Faulty coil - Faulty screened cap 5. Intake circuit - Dirty air filter - Dirty by-pass circuit - Faulty stepper motor 6.
  • Page 239 Nexus 500 Injection - Service key (black) - Deterrent and diagnosis LED Specification Desc./Quantity Main fuse 30 A Fuse 7.5 A Fuse Fuse Stand switch Emergency switch Key switch Engine stop remote control switch Main remote control switch Diode Instrument panel...
  • Page 240 Nexus 500 Injection When the key switch is set to "ON", the LED switches on as shown in the figure. The LED is turned on by the decoder. The control unit data can be checked by the diag- nostic tester.
  • Page 241 Nexus 500 Injection Key number Zero › 250 Setting the circuit The scooter is supplied with two keys: - Master key (red) with removable transponder - Service key (black) with fixed transponder The master and service keys must be used to code the system as follows: - Insert the master key, set to «ON»...
  • Page 242 Nexus 500 Injection WITH SERVICE KEYS Deterring blink Switching from «ON» to «OFF» with programmed system causes the intermittent switching on of the LED, with an antitheft effect. This occurs with any key used for programming. If the scooter is not used, the deterrent light stops automatically after 48 hours to prevent discharging the battery.
  • Page 243 Nexus 500 Injection - Remove the original master key transponder and install it on the master key of the new cylinder. - Program the system again as described above. 2 Decoder replacement When the decoder is replaced it is necessary to program the system again.
  • Page 244 Nexus 500 Injection N.B. TO ACCESS THE COMPONENTS, SEE THE COMPONENTS LAYOUT CHAPTER. Specific tooling 020481Y Control unit interface wiring 1 - Using a multimeter, check the continuity be- tween pin 16 of the control unit and pin 6 of the decoder connector.
  • Page 245 Nexus 500 Injection Program again. 3 - Check the proper connection of the aerial con- nector. YES go to 5 NO go to 4 4 - Restore the connection and check the presence of the code 5 - Disconnect the aerial connector and check con- tinuity (8 ±...
  • Page 246 Nexus 500 Injection Code 4 Code no. 4 denotes a system where the decoder is blank and the control unit is programmed. The key is recognised by the control unit. - Start-up disabled - Indicator light N.B. REPEAT THE KEY PROGRAMMING PROCEDURE USING THE ORIGINAL MASTER KEY.
  • Page 247 Nexus 500 Injection 8 - Check for positive battery voltage on the red/ black cable of the 8-way connector of the instru- ment panel. YES go to 9 NO go to 10 9 - Faulty led, replace the instrument panel.
  • Page 248 Nexus 500 Injection the 4-stroke cycle. Such solution allows controlling the injector and the spark plug every two revolutions of the crankshaft. The sensor is of the reluctance variation type and is therefore comparable to an alternate current gen- erator that powers the control unit.
  • Page 249 Nexus 500 Injection If a signal panel is detected which is not perfectly synchronised, corrective interventions are applied used to reconstruct the cycle. In this case the self-diagnosis records the number of lost synchronisations and signals the fault via the injection telltale light.
  • Page 250 Nexus 500 Injection YES go to 6 NO go to 7 6 The signal panel is in conformance. 7 CHECK THE AIR GAP AND MAGNETIC AC- TIVITY OF THE SENSOR. See engine mechanics. 8 Check the sensor and related connection circuit with the control unit.
  • Page 251 Nexus 500 Injection YES go to 13 NO go to 12 12 - Replace the revolution sensor. 13 - Reconnect the rpm-timing sensor connector. Repeat the resistance check through the injection wiring pin 7, pin 12. Electric characteristic 7-12 = 680 Ω...
  • Page 252 Nexus 500 Injection infinite (>1MΩ) YES go to 19 NO go to 18 18 - Check the sensor and control unit connectors. Repair or replace the injection wiring 19 - Measure the alternated voltage between pins 7 and 12 with engine at start-up speed.
  • Page 253 Nexus 500 Injection CIRCUIT LAYOUT Specification Desc./Quantity Electronic control unit Injector HV coil Pump Control unit remote control switch Fuse 10 A The ignition system is integrated with the injection and it is a high-efficiency inductive type ignition. The control unit manages two important parame-...
  • Page 254 Nexus 500 Injection 4 - Test failed YES go to 6 5 - The coil control circuit is efficient. Check the H.V. coil secondary, the cable and the screened cap 6 - Install the special tool between the injection system and the control unit.
  • Page 255 Nexus 500 Injection N.B. A FAILURE OF THE REMOTE CONTROL SWITCH WOULD CAUSE THE PUMP ROTATION FAIL- 10 - The positive power supply is conforming. Check the continuity between the pink-black wire of the connector and pin 20. Electric characteristic...
  • Page 256 Nexus 500 Injection YES go to 15 NO go to 14 13 - Repair or replace the faulty system. Repeat the check with the menu on "ACTIVE DIAGNOSIS". 14 - Repeat the earth insulation check in the two sections. Repair or replace the wiring. Repeat the check with the menu on "ACTIVE DIAGNOSIS"...
  • Page 257 Nexus 500 Injection YES go to 17 NO go to 1 9 17 - Check the secondary resistance. Measure the resistance between one of the primary terminals and the spark plug cable output Electric characteristic Primary HV cable output = 3.1 K ±...
  • Page 258 Nexus 500 Injection If different values are measured (<1; >20KΩ), re- place the shielded cap. N.B. A SHIELDLESS CAP OR SPARK PLUG CAN ADVERSELY AFFECT THE INJECTION SYSTEM. FOR INFORMATION ON THE SPARK PLUG, SEE THE «SPECIFICATIONS» AND «MAINTE- NANCE» CHAPTERS.
  • Page 259 Nexus 500 Injection - By the driving pulley, turn the engine to find the alignment of the references to identify the TDC. - Repeat for the reference between driving pulley and engine crankcase. - Replace the inspection cap on the flywheel side.
  • Page 260 Nexus 500 Injection 80° = 308 ± 6 Ω CIRCUIT LAYOUT Specification Desc./Quantity Electronic control unit Valve position sensor Air temperature sensor Fluid temperature sensor The coolant temperature sensor is installed on the engine head and provides the indications for the digital instrument and for the injection.
  • Page 261 Nexus 500 Injection Specific tooling 020460Y Scooter diagnosis and tester 2 - The EMS system has received no indications of temperatures out of the range of possible temper- atures. If you suspect a wrong temperature indication, proceed to perform the following check.
  • Page 262 Nexus 500 Injection 9 - Replace the sensor. 10 - Connect the sensor connector and repeat the resistive check at terminals 4 and 22; Electric characteristic 4-22 = Resistance equal to the value directly detected at the sensor. YES go to 13 NO go to 11 11 - If slightly higher values are detected, check the connectors.
  • Page 263 Nexus 500 Injection YES go to 15 NO go to 14 14 - Repair or replace the wiring. Check the air temperature lines and the throttle valve position. YES go to 13 15 - Connect the special tool to the control unit.
  • Page 264 Nexus 500 Injection YES go to 18 Electric characteristic Measured value = Repeat the sensor and circuit earth insulation check. YES go to 19 NO go to 20 19 - Check the control unit connector. Check the control unit power supply.
  • Page 265 Nexus 500 Injection CIRCUIT LAYOUT Specification Desc./Quantity Electronic control unit Valve position sensor Air temperature sensor Fluid temperature sensor The sucked air temperature sensor is installed in the bottom side of the throttle body on the filter box side. The sensor is an NTC and has the same functional layout as the coolant temperature sensor.
  • Page 266 Nexus 500 Injection Check whether there are any indications regarding the sucked air temperature sensor. YES go to 3 NO go to 2 Specific tooling 020460Y Scooter diagnosis and tester 2 - The EMS system has received no indications of temperatures out of the range of possible values.
  • Page 267 Nexus 500 Injection YES go to 10 NO go to 9 9 - Replace the sensor. 10 - Connect the sensor connector and repeat the resistive check at terminals 18 and 22. Electric characteristic 18-22 = Resistance equal to the value directly detected at the sensor.
  • Page 268 Nexus 500 Injection 12 - Repair or replace the cable harness. YES go to 10 13 - Check that the sensor circuit is earth insulated. Electric characteristic 18-23 = infinite (>1MΩ) 22-23 = infinite (>1MΩ) YES go to 15 NO go to 14 14 - Repair or replace the wiring.
  • Page 269 Nexus 500 Injection YES go to 21 NO go to 17 Electric characteristic Measured value = 5±0.2 V Repeat the wiring and sensor continuity checks. YES go to 18 Electric characteristic Measured value = Repeat the sensor circuit earth insulation check.
  • Page 270 Nexus 500 Injection Pressure sensor This sensor does not have a system since it is di- rectly installed into the control unit. The sensor allows the control unit to optimise the engine performance based on altimetric varia- tions. To check the sensor, proceed as follows: 1 - Connect the diagnostic tester.
  • Page 271 Nexus 500 Injection STANDARD: 5 V TERMINALS: 11 - 22 CONDITIONS: Opening the throttle gradually STANDARD: Volt= Progressive increase CIRCUIT LAYOUT Specification Desc./Quantity Electronic control unit Valve position sensor Air temperature sensor Fluid temperature sensor The throttle valve position sensor is not removable and is installed on the throttle body.
  • Page 272 Nexus 500 Injection even though not in an optimum way, always safe- guarding the catalytic converter integrity. The throttle valve position signal is especially im- portant at the small valve openings. These areas are also where the sensor works more frequently, and therefore they require more frequent checks after a high number of kilometres run.
  • Page 273 Nexus 500 Injection 020481Y Control unit interface wiring Electric characteristic Light blue/green-22 = 0 Ω (continuity) Brown-yellow-1 = 0 Ω (continuity) Orange-light blue-11 = 0 Ω (continuity) YES go to 8 NO go to 7 7 - Repair or replace the injection wiring.
  • Page 274 Nexus 500 Injection Measure voltage between terminals 1 and 22 of the special tool. Specific tooling 020481Y Control unit interface wiring Electric characteristic 1-22 = 5±0.2 V YES go to 12 NO go to 11 11 - Check the control unit connector.
  • Page 275 Nexus 500 Injection The possible variations of the limit values are caused by the sensor installation tolerances. YES go to 15 NO go to 14 14 - Replace the throttle body along with sensors and Stepper. YES point 12 15 - Check that the voltage measured at pins 11 and 22 matches that indicated by the diagnostic tester set to "PARAMETERS".
  • Page 276 Nexus 500 Injection Connect the diagnostic tester. Set the switch to "ON" with switch in "RUN" and side stand raised. Select the functions of the diagnostic tester on «TPS RESET». Specific tooling 020460Y Scooter diagnosis and tester Make sure that the throttle valve with the control is supporting the stop screw.
  • Page 277 Nexus 500 Injection THE TPS RESETTING PROCEDURE MUST NOT BE CARRIED OUT WITH A USED THROTTLE BODY BECAUSE POSSIBLE VALVE WEAR AND STOP WEAR FOR THE MINIMUM OPENING MAKE THE AIR FLOW DIFFERENTLY FROM THAT OF PRE-CALIBRATION. Step motor CIRCUIT LAYOUT Specification Desc./Quantity...
  • Page 278 Nexus 500 Injection To prevent wear of the adjustment piston, opera- tion at full speed is obtained with a minimum open- ing of 43 - 45 "steps". To recover possible adjustments, every switching to "OFF" causes the piston to close up to end of travel and to open up again by a fixed number of steps (self-reset).
  • Page 279 Nexus 500 Injection YES go to 3 NO go to 4 3 - Start the engine and let it warm up. With a coolant temperature of more than 70°C, the control unit must control the Stepper with about 45 «steps».
  • Page 280 Nexus 500 Injection Resistance = approx. 51 Ω YES go to 11 NO go to 10 9 - Test successful. No variations of revolutions. Remove the throttle body. Check the auxiliary air circuit cleaning. Switch from "ON" to "OFF" and again to "ON" and check wheth- er the piston valve moves.
  • Page 281 Nexus 500 Injection YES go to 12 NO go to 13 12 - Check the earth insulation of the 4 Stepper lines. Electric characteristic 14-23 = >1 MΩ (infinite) 6-23 = >1 MΩ (infinite) 21-23 = >1 MΩ (infinite) 24-23 = >1 MΩ...
  • Page 282 Nexus 500 Injection YES go to 16 NO go to 15 15 - Check cable harness and connectors more carefully. 16 - Connect the control unit connector. Set the switch to «ON» with switch to «RUN» and side stand raised. Repeat the «ON» «OFF» «ON»...
  • Page 283 INDEX OF TOPICS SUSP USPENSIONS...

  • Page 284: Removing The Front Wheel

    Nexus 500 Suspensions This section is devoted to operations that can be carried out on the suspension. Front Removing the front wheel - Loosen the two wheel axle fastening screws shown in the figure - Remove the wheel axle lock nut.
  • Page 285 Nexus 500 Suspensions - Support the front wheel with two wooden shims to prevent scratches in case of contact with the rim. - Insert the punch consisting of the adapter handle, adapter and 15 mm guide on the odometer motion drive side to allow removing the LH bearing and the spacer bushing.

  • Page 286: Front Fork

    Nexus 500 Suspensions - Upturn the wheel and insert the inside spacer with the portion provided with snap ring facing the LH bearing installed before. - Heat the bearing seat on the odometer motion drive side using the thermal gun.
  • Page 287 Nexus 500 Suspensions Removal - Remove the front wheel. - Remove the front mudguard - Remove the front brake calliper - Remove the front and rear handlebar covers. - Remove the pin mounting the handlebar to the steering tube. - Remove the handlebar and rest it on the shield back plate.
  • Page 288 Nexus 500 Suspensions Servicing tapered bearing seats - Check that the seats and the tapered bearings exhibit no scratches or wear. N.B. THE TAPERED BEARING SEATS SHOULD BE REMOVED ONLY IF STRICTLY NECESSARY. In case of replacement, proceed as follows: - Using a bearing removal punch, inserted from the bottom, remove the top seat on the steering head.
  • Page 289 Nexus 500 Suspensions - Remove the spring. - Drain the oil. - Remove the screw with copper washer shown in the figure. To prevent the pumping member rota- tion, insert an inside 22 mm hexagon spanner into the stem. - Remove the pumping member.
  • Page 290 Nexus 500 Suspensions Refitting Refitting stems on fork legs Preassemble the stem as indicated: - Install the bushing from the bottom of the stem - Insert the following from the top of the stem: 1 Bushing "B" 2 Abutment washer "C"...
  • Page 291 Nexus 500 Suspensions - Insert the contrast spring into the pumping mem- ber. - Insert the pumping member into the stem. - Insert the stem into the fork leg being careful not to let the guiding bushing come out of the stem.
  • Page 292 Nexus 500 Suspensions Stem upper cap 35 - 55 - Loosen the fork clamp screws and move the stem closing cap in abutment with the clamp. - Tighten the clamp screws to the prescribed tor- que. Locking torques (N*m) Fork clamp screws 20 ÷...
  • Page 293 Nexus 500 Suspensions - Install the handlebars on the steering tube, pay- ing attention to the centring, aligning the recess on the handlebar with that on the steering tube as shown in the figure. - Tighten the handlebar fixing screw on the steering tube to the prescribed torque.
  • Page 294 Nexus 500 Suspensions - Insert the special tool as shown in the figure. - Insert the retaining band of the two half-rings. - Using a 19 mm hexagonal spanner, extract the roller bearing. Specific tooling 020458Y Puller for lower bearing on steering...

  • Page 295: Assembly Plate Mounting On Strut Support

    Nexus 500 Suspensions ALWAYS USE A NEW BEARING AND A NEW SEAT. Specific tooling 001330Y Tool for fitting steering seats Reassembly of tapered bearing in steering tube - Insert the a new plate and a new dust guard in the steering tube...
  • Page 296 Nexus 500 Suspensions Recommended products Loctite 243 Medium strength threadlock Loctite 243 medium-strength threadlock The scooter has a "Power Drive" progressive rear suspension system combined with the "Direct Link" system of engine mounting on the frame that gives exceptional rigidity to the whole system.

  • Page 297: Removing The Rear Wheel

    Nexus 500 Suspensions Removing the rear wheel - Remove the muffler support arm - Remove the spacer on the gear shaft. - Loosen the five gear shaft fastening nuts using the rear brake. Refitting the rear wheel - For reassembly, perform the previous operations in the reverse order...

  • Page 298: Shock Absorbers

    Nexus 500 Suspensions Removal - Support the engine adequately. - Remove the pin anchoring the engine to the chassis. - Move the engine backwards to take out spacers - Remove the left spacer highlighted in the figure. - Remove the central and the right spacer.
  • Page 299 Nexus 500 Suspensions Removal - To remove the rear shock absorber, remove the two retaining screws shown in the figure. Refitting - To refit perform the operation in reverse order carefully respecting the locking torques. Locking torques (N*m) Rear shock absorber retainer to the chassis 38 - 46...

  • Page 300: Side Stand

    Nexus 500 Suspensions Side stand - Unhook the springs. - Loosen the nut. - Pull out the screw. Fitting Carry out the previous operations but in reverse order. Locking torques (N*m) Side stand clamp 15 ÷ 20 SUSP - 300...
  • Page 301 INDEX OF TOPICS BRAK SYS RAKING SYSTEM...
  • Page 302 Nexus 500 Braking system Specifications The scooter has an integral brake system. This is obtained with the left-hand brake pump connected simultaneously to the rear brake calliper and the front right calliper. The connection to the rear calliper is direct.

  • Page 303: Rear Brake Calliper

    Nexus 500 Braking system Specification Desc./Quantity Rear brake pressure Front brake pressure Rear brake calliper Removal - Remove the rear wheel. - Remove the snap ring of the pad retaining pin. - Using a key, partially slide off the pad retaining pin until the circlip is released.
  • Page 304 Nexus 500 Braking system Overhaul - Remove the rear brake calliper - Suitably support the brake calliper in a vice - Remove the two calliper coupling screws as shown in the photograph. - Remove the two plungers from the calliper body with the aid of short blasts of compressed air through the brake fluid feed holes.
  • Page 305 Nexus 500 Braking system Refitting - The rear break calliper can be recognised by its Ø 34 mm plungers and the bleed screw as shown in the figure. - Insert the break pads in the pliers according to the arrow that indicates the break disc direction of rotation as shown in the photograph.
  • Page 306 Nexus 500 Braking system - Keep the brake pads in contact with the plungers and insert the calliper in the brake disc. - Fix the calliper to the support with the two screws with spring washer to the prescribed torque as shown in the photograph.
  • Page 307 Nexus 500 Braking system Overhaul - Remove the front brake calliper and the corre- sponding pads. - Remove the two pistons from the calliper body with the aid of small blasts of compressed air through the brake fluid feeding hole. A piece of rubber pipe may be needed to seal with the com- pressor gun.
  • Page 308 Nexus 500 Braking system - Decouple the floating support of the calliper body separating the 2 rubber dust-covers off their seats. N.B. TO EXTRACT THE LONG DUST-COVER PULL IT BY ITS HEAD AND INTRODUCE THE BELLOWS ( LOCATED ON THE OTHER SIDE) INTO THE CALLIPER HOLE. LUBRI- CATE THE SLIDING PINS WITH SPECIFIC GREASE (AP- PROPRIATE FOR RUBBER GASKETS).
  • Page 309 Nexus 500 Braking system Refitting - To reassemble the brake disc on the hub, carry out the removal operations in the reverse order ar- ranging the brake disc on the hub on the side opposed the wheel keying - Follow the direction of rotation shown by the ar- row and tighten to the prescribed torque.

  • Page 310: Front Brake Disc

    Nexus 500 Braking system - Repeat the measurement in at least 6 points of the disc. - Check that the measurements do not give devi- ations higher than ..- Check that the brake disc unit rotates regularly using the specific tool fixed on the brake caliper support as shown in the figure.
  • Page 311 Nexus 500 Braking system Refitting - Perform the removal operations in the reverse order according to the direction of rotation of the disc, as shown by the arrow on the disc - Tighten the 5 screws at the prescribed torque.

  • Page 312: Front Brake Pads

    Nexus 500 Braking system Front brake pads Removal - Remove the front brake calliper unscrewing the 2 retainers but leaving the hoses connected. - Disengage the upper part of the pad from the seat located into the calliper body. - Using a calliper, remove the 2 retaining pins of the pad sliding pin.
  • Page 313 Nexus 500 Braking system Refitting - Assemble the brake pads into the calliper insert- ing the upper tip into the groove and pressing it towards the thrust spring to facilitate inserting the pin. - Insert the pad fixing pin from the reaction plate side, so that the pin head clicks in the seat in the groove on that plate.
  • Page 314 Nexus 500 Braking system Removal - Remove the rear brake calliper - Remove the brake pad and check there are no faults or warping. If it does, replace it. - Check that the thickness of the friction material is over 1.5 mm. Otherwise, replace it.
  • Page 315 Nexus 500 Braking system Rear - combined To bleed the integral system, first bleed the rear break calliper. - Remove the rubber cap from the bleed screw and insert a rubber pipe to recover the brake fluid. - With the left-had brake lever, load the system and bring it up to the required pressure.
  • Page 316 Nexus 500 Braking system Circuit bleed calliper fitting 12 - 16 Front - Remove the rubber hood from the bleed screw. - Insert a rubber pipe in the bleed screw to permit the brake fluid to be recovered. - With the right-hand brake lever, load the system and bring it up to the required pressure.
  • Page 317 Nexus 500 Braking system Removal - Remove the front handlebar cover. - Drain off the braking system corresponding to the circuit being tested. - Remove the two fixing screws from the brake pump to the handlebar indicated in the photo- graph.
  • Page 318 Nexus 500 Braking system Removal Replace the pressure distribution valve If problems are discovered in the brake force dis- tribution between the front left brake calliper and the rear brake calliper (e.g. equal surface contact and braking of both the wheels, the rear brake en-...
  • Page 319 Nexus 500 Braking system - Tighten the screws fixing the valve to the chassis, but above all tighten the brake piping to the pre- scribed locking torques. - Fill and purge the braking system as described in the relevant section.
  • Page 320 INDEX OF TOPICS COOL SYS OOLING SYSTEM...
  • Page 321 Nexus 500 Cooling system Circuit diagram The cooling system is a forced circulation type system, with continuous venting and air pressurisation. Circulation takes places by a centrifugal pump driven by the countershaft. The pump delivers the coolant to the thermal group.
  • Page 322 Nexus 500 Cooling system For the system venting during the circuit filling step, there is a special union at the top of the head (see filling rules). To ensure cooling in case of poor dynamic ventilation, there is an electric fan controlled by the injection system.
  • Page 323 Nexus 500 Cooling system - Select the menu on the "ACTIVE DIAGNOSIS" function and start the electric fan operation simu- lation (see "Injection" chapter). - If the electric fan is certainly efficient, check the ventilation start and stop temperatures. - Select the «PARAMETERS» function in this menu to display the coolant temperature.

  • Page 324: Coolant Replacement

    Nexus 500 Cooling system DO NOT USE OILS OR GREASES WHILE MOUNTING THE COOLING SYSTEM. FAILURE TO OB- SERVE THIS REGULATION CAN CAUSE IRREVERSIBLE DEFORMATION TO THE SEALING GASKETS. Coolant replacement System top-up instructions - Prepare the mixture of 50% water and 50% cool- ant.
  • Page 325 Nexus 500 Cooling system Water pump - overhaul - Check that the reed valve of blow-by circuit closes adequately. - Check that the water pump shaft does not show signs of wear and tear on the bearings in contact with the crankcase, in the oil seal area and on the motion sensor.

  • Page 326: Water Pump Cover Screws

    Nexus 500 Cooling system - Check that the water pump cover is not damaged or deformed. - Check that the sealing O-Ring is in good condi- tion - Carefully position a new O-Ring, avoiding contact with grease or oil. CAUTION FAILURE TO OBSERVE THIS ADVICE CAN IRRETRIEVABLY DEFORM THE O-RING.
  • Page 327 Nexus 500 Cooling system - Check that the rotor does not show deformations or dents. - Check that the plastic rotor forms an integral unit with the metal part. Thermostat Check Before proceeding to disassemble, carry out a few checks: - Connect the diagnostic tester and select the «PA-...
  • Page 328 Nexus 500 Cooling system - Visually check that the thermostat exhibits no mechanical faults. - Prepare a metal container with approx. 1 litre of water. - Immerse the thermostat, keeping it in the centre of the container. - Immerse the multimeter temperature probe close to the thermostat.
  • Page 329 Nexus 500 Cooling system N.B. THE CAP IS EQUIPPED WITH A PRESSURE RELIEF VALVE CALIBRATED AT 0.9 BAR. There is also a valve that must allow air inlet during the cooling step. YES go to 2 NO go to 3 2 - Check the head gasket seal (see «Thermal group and timing system»...
  • Page 330 INDEX OF TOPICS CHAS HASSIS...
  • Page 331 Nexus 500 Chassis This section is devoted to the operations that can be carried out on the vehicle bodywork. CAUTION WE STRONGLY RECOMMEND NOT TO CLEAN THE PAINTED PLASTIC PARTS WITH SOLVENTS CONTAINING PETROL OR PETROL BY-PRODUCTS. Seat - Remove the saddle extracting the fixing pin of the gas shock absorber and the 2 chassis fixing screws.

  • Page 332: Instrument Panel

    Nexus 500 Chassis - Remove the frames of the brake pump on the left and right secured with 2 locking tabs. - Loosen the 4 retaining screws of the front han- dlebar cover with the handlebar proper. Remove the 4 pressure indicator lights from the warning light group, pulling them downwards.
  • Page 333 Nexus 500 Chassis Headlight assy. - Remove the centre cover of the shield. - Remove the 4 front retainers of the front light as- semblies. - To remove the right-hand light assembly, remove the screw located near the cover of the expansion tank.
  • Page 334 Nexus 500 Chassis Frame central cover - Remove the screw shown in the figure. - Disengage the 6 coupling teeth and remove the complete grid. - Remove the side cover. - Remove the saddle. - Remove the fuel port. - Remove the side grids.
  • Page 335 Nexus 500 Chassis - Remove the front shield, disconnecting the wiring and the connectors of the headlights and lights. Remove the 3 screws as shown in the figure. - Paying attention not to damage the plastic parts, release the 3 upper retainers of the windshield support and the 4 side retainers of the front shield.
  • Page 336 Nexus 500 Chassis - Remove the front fuse holder, levering out using a flat screwdriver on the tab located on the side (on the side of the key switch). - Remove the 2 screws located inside the storage compartment and the coolant top-up compartment (in order not to have to remove the front headlight).
  • Page 337 Nexus 500 Chassis Removing the ignition key-switch when on *off* - Remove the lower shield back plate. - Unscrew the seat opening transmission from the side. - Remove in advance the ring of the immobiliser antenna. - Loosen the 2 hex. socket head screws and re- move the complete switch.
  • Page 338 Nexus 500 Chassis Front wheel housing - Remove the spoiler. - Remove the front fork. - Remove the plate supporting bracket for the horn and voltage regulator by loosening the two retain- ing screws shown in the figure in order to release the two lower retainer of the wheel housing.
  • Page 339 Nexus 500 Chassis - Using a 10mm articulated wrench, between the under saddle compartment and the chassis tubes loosen the 2 rear fixing nuts, then disengage the stud bolts from the support tails. Footrest - Remove the centre union. - Remove the side fairings.
  • Page 340 Nexus 500 Chassis Side fairings - Remove the side rear union. - Remove the passenger handles. - Remove the bottom cover. - Remove the footboard supports - Remove the central union. - Remove the screws shown in the figure (in the left side, a screw is located below the air inlet union of the filter).
  • Page 341 Nexus 500 Chassis Air filter - Remove the helmet compartment. - Remove the straps of the oil vapour recovery hose and the air bellows shown in the figure. - Loosen the two screws shown in the figure. - Loosen the two retainers shown in the figure and remove the complete air filter.

  • Page 342: Rear Mudguard

    Nexus 500 Chassis Rear mudguard - Remove the two clamps shown in the figure. - Remove the retainer of the mudguard/strut rein- forcement plate to remove the complete mud- guard. Helmet bay - Remove the side panels - Remove the six upper clamping screws.
  • Page 343 Nexus 500 Chassis - Remove the 3 screws located inside the com- partment in the rear part providing the mounting for the electrical system of the saddle opening de- vice and for the support of the transmission. - Disconnect the connectors of the power socket and the under-saddle light.
  • Page 344 Nexus 500 Chassis - Remove the 4 union screws with the front wheel housing cover. - Pull the spoiler from the lower part of the scooter. Fuel tank - Open the tank port. - Remove the hex screw shown in the figure.
  • Page 345 Nexus 500 Chassis THIS OPERATION SHOULD PREFERABLY BE PERFORMED WITH THE TANK EMPTY. - Remove the spoiler; - Remove the fuel filler. - Remove the two upper tank attachments high- lighted in the figure. - Remove the fuel pump retainers.

  • Page 346: Front Mudguard

    Nexus 500 Chassis Front mudguard - Remove the 4 retaining screws and pull the mud- guard towards the front of the scooter. - Pay attention during assembly to the correct po- sitioning of the retaining straps of the hoses. Radiator fan - Remove the spoiler.
  • Page 347 Nexus 500 Chassis Handles and top side fairings - Remove the three screws indicated in the figure. - Remove the 2 hex. socket head screws and then the passenger handgrips on the left and right. Flyscreen - Remove the 3 hex. socket head screws (when...
  • Page 348 Nexus 500 Chassis - Remove the plugs and remove the seals on the 2 lateral windshield support arms. - Remove the plastic cover from the windshield support, loosening the 5 screws shown in the fig- ure. - Disengage the 7 retaining tabs (3 with the shield back plate, 4 with the shield).

  • Page 349: Lower Cover

    Nexus 500 Chassis Battery - Remove the elastic strap and the battery cover. Lower cover - Remove the two rear screws shown in the figure. - Remove the 4 bottom screws shown in the figure and the complete bottom cover.
  • Page 350 INDEX OF TOPICS PRE DE DELIVERY...
  • Page 351 Nexus 500 Pre-delivery Carry out the listed tests before delivering the vehicle. WARNING BE VERY CAREFUL WHEN HANDLING FUEL. Aesthetic inspection Appearance check: - Paintwork - Fitting of plastics - Scratches - Dirt Tightening torques inspection Lock check - Safety locks...
  • Page 352 Nexus 500 Pre-delivery CAUTION TO ENSURE MAXIMUM PERFORMANCE, THE BATTERY MUST BE CHARGED BEFORE USE. INADEQUATE CHARGING OF THE BATTERY WITH A LOW LEVEL OF ELECTROLYTE BEFORE IT IS FIRST USED SHORTENS BATTERY LIFE. CAUTION WHEN INSTALLING THE BATTERY, CONNECT THE POSITIVE CABLE BEFORE CONNECTING THE NEGATIVE ONE, AND PERFORM THE REVERSE OPERATION UPON REMOVAL.
  • Page 353 Nexus 500 Pre-delivery - Starter operation - Minimum hold (turning the handlebar) - Uniform turning of the steering - Possible leaks - Operation of the radiator electric fan Functional inspection Operating test: - Hydraulic brake system - Lever travel - Clutch - Check for correct operation...
  • Page 354 INDEX OF TOPICS TIME...
  • Page 355 Nexus 500 Time This section is devoted to the time necessary to carry out repairs. For each operation, the description, code and time envisages are specified. Engine ENGINE Code Action Duration 001001 Engine to chassis - Replacement TIME - 355...
  • Page 356 Nexus 500 Time Crankcase CRANKCASE Code Action Duration 001100 Oil seal, clutch side - Replacement 001133 Engine crankcase- Replacement 001153 Crankcase half gasket - Replace- ment TIME - 356...
  • Page 357 Nexus 500 Time Crankshaft CRANKSHAFT Code Action Duration 001117 Crankshaft - Replacement 001098 Countershaft - Replacement TIME - 357...
  • Page 358 Nexus 500 Time Cylinder assy. CYLINDER GROUP Code Action Duration 001002 Cylinder piston - Replacement 001154 Pin-ring-piston assembly - Service 001129 Chain tensioner - Service and Re- placement TIME - 358...
  • Page 359 Nexus 500 Time Cylinder head assy. HEAD UNIT Code Action Duration 001045 Valves - Replacement 001049 Valves - Adjustments 001056 Head gasket - Replacement 001126 Head - Replacement 001083 Thermistor - Replacement 005116 Rpm timing sensor - Replacement 007012 Coolant bleed valve - Replacement...
  • Page 360 Nexus 500 Time Rocker arms support assy. ROCKING LEVER SUPPORT UNIT Code Action Duration 001044 Camshaft - Replacement 001148 Rocking lever valve - Replacement TIME - 360...

  • Page 361: Cylinder Head Cover

    Nexus 500 Time Cylinder head cover HEAD COVER Code Action Duration 001089 Head cover - Replacement 001093 Spark plug - Replacement 001088 Head cover gasket - Replacement TIME - 361...
  • Page 362 Nexus 500 Time Flywheel cover FLYWHEEL COVER Code Action Duration 001087 Flywheel cover - Replacement 001113 Water pump - Replacement 001123 Oil filter -Replacement 001124 By-pass valve - Replacement 001057 Thermostat - Replacement 001062 Water pump command shaft - Re-...

  • Page 363: Driven Pulley

    Nexus 500 Time Driven pulley DRIVEN PULLEY Code Action Duration 001022 Clutch - Replacement 001012 Driven pulley - Overhaul 001110 Driven pulley - Replacement 001155 Clutch bell housing - Replacement TIME - 363...
  • Page 364 Nexus 500 Time Oil pump OIL PUMP Code Action Duration 001042 Oil pump - Service 001051 Belt/ Timing chain - Replacement 001112 Oil pump - Replacement 001125 Chain guide sliders - Replacement 001071 Start-up pinion - Replacement 001020 Starter motor - Replacement...
  • Page 365 Nexus 500 Time Final gear assy. FINAL REDUCTION GEAR ASSEMBLY Code Action Duration 001010 Geared reduction unit - Service 001156 Gear reduction unit cover - Replace- ment 003065 Gear box oil - Replacement 004125 Rear gear shaft - Replacement TIME - 365...
  • Page 366 Nexus 500 Time Driving pulley DRIVING PULLEY Code Action Duration 001086 Driving half-pulley - Replacement 001011 rear-view belt - Replacement 001006 rear-view pulley - Service 001141 Belt anti-flapping roller - Replace- ment 001066 rear-view pulley - Replacement TIME - 366...
  • Page 367 Nexus 500 Time Transmission cover TRANSMISSION COVER Code Action Duration 001065 Internal transmission cover - Re- placement 001096 External transmission cover - Re- placement 001131 Transmission air intake - Replace- ment 001135 Transmission cover bearing - Re- placement 001170 Air manifold - replacement...

  • Page 368: Flywheel Magneto

    Nexus 500 Time Flywheel magneto MAGNETO FLYWHEEL Code Action Duration 001173 Rotor - Replacement 001067 Stator - Replacement 001058 Flywheel - Replacement 001104 Start-up freewheel - Replacement 001151 Start-up driven gearing - Replace- ment TIME - 368...

  • Page 369: Throttle Body

    Nexus 500 Time Butterfly valve THROTTLE BODY Code Action Duration 001013 Intake manifold - Replacement 001047 Injector - Replacement 001166 Throttle body - Replacement 004122 Cleaner / Throttle body union - Re- placement 001171 Throttle body - Service/cleaning TIME - 369...
  • Page 370 Nexus 500 Time Exhaust pipe SILENCER Code Action Duration 001009 Muffler - Replacement 001092 Exhaust manifold - Replacement 001095 Muffler guard - Replacement 001136 Exhaust emissions - Adjustment 004169 Muffler guard - Replacement TIME - 370...

  • Page 371: Air Cleaner

    Nexus 500 Time Air cleaner AIR CLEANER Code Action Duration 001015 Air filter box - change 001014 Air filter - Replacement/Cleaning 001074 Oil vapour recovery pipe - Replace- ment TIME - 371...
  • Page 372 Nexus 500 Time Frame FRAME Code Action Duration 004001 Frame - replace 004146 Front frame - Replacement 001032 Engine support pin - Replacement TIME - 372...
  • Page 373 Nexus 500 Time Centre-stand SIDE/CENTRAL STAND Code Action Duration 004004 Stand - Replacement 004102 Side stand - Replacement 005079 Side stand switch - Replacement 004171 Stand support plate - Replacement TIME - 373...
  • Page 374 Nexus 500 Time Legshield spoiler FRONT SHIELD - SPOILER Code Action Duration 004066 Driving mirror - Replacement 005091 Turn indicator glass - Replacement 005067 Front direction indicator bulb - Re- placement 004064 Front shield - Replacement 004149 Shield central cover - Replacement...
  • Page 375 Nexus 500 Time Central cover CENTRAL FRAME COVER Code Action Duration 004011 Central chassis cover - Replacement 004104 Left side cover - Replacement 004105 Right side cover - Replacement 004079 Rear footrest - Replacement 004143 Footrest support - replace TIME - 375...
  • Page 376 Nexus 500 Time Mudguard MUDGUARDS Code Action Duration 004167 Grill / radiator cover - replace 004009 Rear mudguard - Replacement 004002 Front mudguard - change 003087 Wheel housing - Replacement TIME - 376...
  • Page 377 Nexus 500 Time Fuel tank FUEL TANK Code Action Duration 004005 Fuel tank - replace 004170 Tank filler neck - Replacement 004168 Fuel filler flap - Replacement 004109 Fuel tank breather - replace TIME - 377...
  • Page 378 Nexus 500 Time Handlebar covers HANDLEBAR COVERS Code Action Duration 004018 Handlebar front section - Replace- ment 004019 Handlebar rear section - Replace- ment 005129 Warning light group - Replacement 004156 Glove-box flap - Replacement 005038 Instrument panel warning light bulbs...
  • Page 379 Nexus 500 Time Handlebar components HANDLEBAR COMPONENTS Code Action Duration 003001 Handlebar - Replacement 005017 Stop switch - Replacement 002037 Brake or clutch lever - Replacement 002060 Complete gas command - Replace- ment 002059 Right hand grip - Replacement 003059...
  • Page 380 Nexus 500 Time Seat SADDLE Code Action Duration 004003 Saddle - Replacement 004150 Saddle shock absorber - Replace- ment TIME - 380...
  • Page 381 Nexus 500 Time Locks LOCKS Code Action Duration 004010 Antitheft lock - Replacement 005099 Electric saddle opening device - Re- placement 002083 Saddle opening transmission - Re- placement 002092 Seat locking transmission - replace- ment 004054 Saddle lock catch - Replacement...

  • Page 382: Turn Signal Lights

    Nexus 500 Time Turn signal lights REAR LIGHTS Code Action Duration 005005 Taillight - change 005022 Rear turn indicators - Replacement 005068 Rear turn indicator bulb- Replace- ment 005091 Turn indicator glass - Replacement 005031 Licence plate light bulb - Replace-...
  • Page 383 Nexus 500 Time FRONT LIGHTS Code Action Duration 005002 Front headlamp - replace 005008 Front headlamp bulbs - replace 005044 Front lights cable unit - replace TIME - 383...

  • Page 384: Front Wheel

    Nexus 500 Time Front wheel FRONT WHEEL Code Action Duration 005089 Tone wheel - Replacement 002041 Front brake disc - Replacement 003037 Front wheel rim- Replacement 003038 Front wheel axle - Replacement 003040 Front wheel bearings - Replacement 003047 Front tyre - Replacement...
  • Page 385 Nexus 500 Time Rear wheel REAR WHEEL Code Action Duration 001016 Rear wheel - Replacement 001017 Rear wheel rim - replace 002070 Rear brake disc - Replacement 003063 Tyre pressure - Check 003077 Muffler / rear shock absorber support arm - Service...

  • Page 386: Fuel Pump

    Nexus 500 Time Fuel pump FUEL PUMP Code Action Duration 004073 Fuel pump - Replacement 004137 Injector pump pipe - Replacement TIME - 386...
  • Page 387 Nexus 500 Time Electric devices ELECTRIC DEVICES Code Action Duration 005001 Electrical system - Replacement 005054 Fuse holder - Replacement 005052 Fuse (1) - Replacement 005114 Electrical system - Service 005130 Electric control management device - Replacement TIME - 387...
  • Page 388 Nexus 500 Time ELECTRIC DEVICES Code Action Duration 001023 Injection ECU - Replacement 005009 Voltage regulator - Replacement 005117 Electric fan remote control - Replace- ment 005088 Emergency stop remote control - Re- placement 005096 Injection components remote control - Replacement...
  • Page 389 Nexus 500 Time ELECTRIC DEVICES Code Action Duration 005127 Overturn sensor - replacement 001069 HV coil - Replacement 005007 Battery - Replacement 005046 Battery cover - Replacement 005073 Immobilizer decoder - Replacement 005011 Start-up remote control switch - Re- placement...
  • Page 390 Nexus 500 Time HANDLEBAR ELECTRICAL COMPONENTS Code Action Duration 004035 Instrument panel - Replacement 005014 Odometer assembly - replacement 005083 Board computer - replacement 003074 Handlebar right control - Replace- ment 003075 Handlebar left control - Replacement 005082 Instrument unit wiring - replacement...

  • Page 391: Helmet Compartment

    Nexus 500 Time Helmet bay HELMET COMPARTMENT Code Action Duration 004016 Helmet compartment - replace 005033 Glove-box light switch - Replace- ment 005026 Helmet compartment light - Replace- ment 004142 Plug socket - Replacement 005027 Helmet compartment bulb support -...
  • Page 392 Nexus 500 Time Rear side fairings REAR COVERS Code Action Duration 004053 Spoiler - Replacement 004085 Rear fairing - Replacement 004068 Passenger handgrip - Replacement 004159 Plates / Stickers - Replacement 004036 Lower chassis cover - Replacement 004012 Rear side panels (2) - Replacement...
  • Page 393 Nexus 500 Time Front suspension FRONT SUSPENSION Code Action Duration 003051 Complete fork - Replacement 003010 Front suspension - service 003076 Fork housing - replacement 003079 Fork stem - Replacement 003048 Fork oil seal - Replacement 003073 Steering clearance - Adjustment...
  • Page 394 Nexus 500 Time Rear suspension REAR SUSPENSION Code Action Duration 003085 Suspension strut - Replacement 003007 Rear shock absorber - Replacement 004120 Rear suspension linkage - Replace- ment 003086 Suspension strut support - replace- ment TIME - 394...
  • Page 395 Nexus 500 Time Cooling system COOLING SYSTEM Code Action Duration 007002 Water cooling radiator - Replace- ment 007016 Fan with support - Replacement 007001 Expansion tank - Replacement 007024 Expansion tank cap - Replacement 007019 Coolant return pipe - replacement...

  • Page 396: Brake System

    Nexus 500 Time Braking system BRAKE SYSTEM Code Action Duration 002021 Front brake piping - Replacement 002047 Front brake fluid and air bleeding system - Replacement 002020 Rear brake disc piping - Replace- ment 002087 Rear integral braking system rigid...
  • Page 397 Nexus 500 Time Windscreen WINDSHIELD Code Action Duration 004028 Windshield glass - Replacement 004101 Windshield - Replacement 004117 Top fairing - Replacement TIME - 397...
  • Page 398 Air filter: 37, 341 Battery: 54, 56, 63, 64, 71, 349 Brake: 303, 306, 308, 310, 312, 313, 316, 317 Coolant: 259, 324 Engine oil: 38 Fuel: 13, 212, 223, 227, 344, 377, 386 Fuses: 58 Headlight: 44, 333 Hub oil: 35 Identification: 8 Immobilizer: Instrument panel: 332...
  • Page 399 Technical Data: Transmission: 9, 77, 93, 367 Tyres: 10...

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