APRILIA SX 125 Service Station Manual
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APRILIA SX 125 Service Station Manual

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SERVICE STATION MANUAL
854196
RX SX 125

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Summary of Contents for APRILIA SX 125

  • Page 1 SERVICE STATION MANUAL 854196 RX SX 125...
  • Page 2 The descriptions and illustrations given in this publication are not binding; While the basic characteristics as described and illustrated in this manual remain unchanged, aprilia 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 manual provides the main information to carry out regular maintenance operations on your vehicle. - This manual is intended to aprilia Dealers and their qualified mechanics; several concepts have been deliberately omitted as they are considered unnecessary. As it is not possible to include complete mechanical notions in this manual, users should have basic mechanical knowledge or minimum knowledge about the procedures involved when repairing scooters.
  • Page 5 INDEX OF TOPICS CHAR HARACTERISTICS S-TOOLS PECIAL TOOLS MAIN AINTENANCE TROUBL ROUBLESHOOTING ELE SYS LECTRICAL SYSTEM ENG VE NGINE FROM VEHICLE NGINE P SUPP OWER SUPPLY SUSP USPENSIONS CHAS HASSIS COOL SYS OOLING SYSTEM BODYW ODYWORK PRE DE DELIVERY...
  • Page 6 INDEX OF TOPICS CHAR HARACTERISTICS...

  • Page 7: Safety Rules

    RX SX 125 Characteristics Rules Safety rules Carbon monoxide If you need to keep the engine running while working on the vehicle, please ensure that you do so in an open or very well ventilated area. Never run the engine in an enclosed area. If you do work in an enclosed area, make sure to use a fume extraction system.
  • Page 8 RX SX 125 Characteristics KEEP OUT OF THE REACH OF CHILDREN DO NOT REMOVE THE RADIATOR CAP WHEN THE ENGINE IS STILL HOT. THE COOLANT IS PRESSURISED AND MAY CAUSE SCALDING. Used engine oil and transmission oil CAUTION IT IS ADVISABLE TO WEAR LATEX GLOVES WHEN SERVICING THE VEHICLE.
  • Page 9 REASSEMBLING COMPONENTS CAUTION BEARINGS MUST ROTATE FREELY, WITHOUT JAMMING AND/OR NOISE, OTHERWISE, THEY NEED TO BE REPLACED. • Only use ORIGINAL Aprilia SPARE PARTS. • Comply with lubricant and consumables use guidelines. • Lubricate parts (whenever possible) before reassembling them.

  • Page 10: Vehicle Identification

    RX SX 125 Characteristics • Grip the two connectors and disconnect them by pulling them in opposite directions. • If any signs of dirt, rust, moisture, etc. are noted, clean the inside of the connector carefully with a jet of compressed air.
  • Page 11 RX SX 125 Characteristics CHASSIS NUMBER The chassis number is stamped on the right side of the headstock. ENGINE NUMBER The engine number is stamped on the rear side, next to the shock absorber. Dimensions and mass DIMENSIONS SIZES SX 125...
  • Page 12 RX SX 125 Characteristics GEAR Specification Desc./Quantity Type mechanic, 6 gear with pedal lever on the left hand side of the engine Gear lubrication Splash lubrication Transmission TRANSMISSION TRANSMISSION SX 125 RX 125 Gear ratio 19/63 = 1 :3.316 19/63 = 1 :3.316 1st gear ratio 10/30 = 1:3.000...

  • Page 13: Warning Lights

    RX SX 125 Characteristics ELECTRICAL SYSTEM SX 125 RX 125 (Permanent magnet) Generator 12V - 180W 12V - 180W BULBS BULBS SX 125 RX 125 License plate bulb Rear tail light /stop light Front tail bulb 2V x 3W 2V x 3W...

  • Page 14: Wheels And Tyres

    RX SX 125 Characteristics Wheels and tyres WHEEL RIMS WHEEL RIMS SX 125 RX 125 Front 3.00/17" 1.6/21" Rear 4.25/17" 2.15/18" TYRES TYRES SX 125 RX 125 Type Radial Radial Front 110/70 R17 M/C 54H TL 90/90 - 21 54R MT 21...

  • Page 15: Rear Suspension

    RX SX 125 Characteristics Name Torque in Nm Lower plate retainer - M6x30 (4) 10 Nm (7.37 lbf ft) Foot lock on wheel pin - M6x25 (2) 10 Nm (7.37 lbf ft) Bearing pack ring nut preloading (1) 17 Nm (12.54 lbf ft) Bearings pack ring nut (1) 7 Nm (5.16 lbf ft)
  • Page 16 RX SX 125 Characteristics RONT BRAKE Name Torque in Nm Front brake calliper to fork feet retainer - TE M8x30 screw (2) 25 Nm (18.44 lbf ft) Front brake pipe to stem protection retainer - TE M5x16 screw 5 Nm (3.69 lbf ft) Front brake pipe to stem protection retainer - M5 nut (2) 5 Nm (3.69 lbf ft)
  • Page 17 RX SX 125 Characteristics Name Torque in Nm Instrument panel support / tank to upper plate retainer - TCEI 10 Nm (7.37 lbf ft) M6x30 screw (1) Tank cover to chassis retainer - TE M6x30 screw (1) 10 Nm (7.37 lbf ft) Tank cover to tank retainer - TBEI M5 screw (2) 5 Nm (3.69 lbf ft)
  • Page 18 INDEX OF TOPICS S-TOOLS PECIAL TOOLS...
  • Page 19 RX SX 125 Special tools PECIAL TOOLS Stores code Description AP0277215 Buffer for fitting oil seal 250455 AP0277875 Buffer for fitting oil seal 230425 AP0276502 Buffer for fitting oil seal 930675 AP0276770 Buffer for fitting oil seal 230195 AP0277970 Guide bushing for oil seal 930675...
  • Page 20 RX SX 125 Special tools Stores code Description AP0276040 Clutch wrench 11 mm AP0277180 Bearing tie rod kit AP0277455 Extractor plate to separate the crankcase halves AP0276380 bolt M10 AP0276370 Split bushing AP0242091 Hexagon nut M10 AP0276382 Bolt S-TOOLS - 20...
  • Page 21 RX SX 125 Special tools Stores code Description AP0276372 Split bushing AP0242700 Flanged nut M8 AP0277445 Guillotine extractor AP0277917 Brackets AP0276025 Half-ring AP0977490 Ring for half-rings AP0876298 Extractor for crankshaft bearings S-TOOLS - 21...
  • Page 22 RX SX 125 Special tools Stores code Description AP0840681 Allen screw for extractor M8x40 AP8146486 Front service stand AP8140192 Chain fitting kit AP8140180 Extractor for bushings AP8705021 Rear service stand AP8140204 Supports for rear service stand AP8140199 Tool panel S-TOOLS - 22...
  • Page 23 RX SX 125 Special tools Stores code Description AP8101945 Fork pin ring nut S-TOOLS - 23...
  • Page 24 INDEX OF TOPICS MAIN AINTENANCE...

  • Page 25: Maintenance Chart

    RX SX 125 Maintenance Maintenance chart SX RX 125 R OUTINE AINTENANCE ABLE I: INSPECT AND CLEAN, ADJUST, LUBRICATE OR REPLACE IF NECESSARY C: CLEAN, R: REPLACE, A: ADJUST, L: LUBRICATE * Replace every year ** Replace every 2 years *** Replace every 4 years **** Lubricate the chain every 500 km (310.98 mi)

  • Page 26: Gearbox Oil

    RX SX 125 Maintenance • Take out the spark plug tube. • Remove the spark plug with the sup- plied wrench. Gearbox Oil Inspection NOTE PARK THE VEHICLE ON SAFE AND LEVEL GROUND. • Stop the engine and let it cool off for at least ten minutes so that the oil in the crankcase flows down and cools as well.
  • Page 27 RX SX 125 Maintenance TIGHTEN UP THE FILLER CAP AND MAKE SURE THE OIL DOES NOT SEEP. CHECK REGULARLY THAT THERE ARE NO LEAKS IN THE CRANKCASE COVER GASKET. DO NOT RIDE THE VEHICLE WITH INSUFFICIENT LUBRICATION OR WITH CONTAMINATED OR INCORRECT LUBRICANTS AS THIS ACCELERATES THE WEAR AND TEAR OF THE MOVING PARTS AND CAN CAUSE IRRETRIEVABLE DAMAGE.

  • Page 28: Air Filter

    RX SX 125 Maintenance • Screw the filler plug (1). • Start the engine and let it idle for about a minute to allow the gearbox oil circuit to get filled. • Check the oil level and refill if necessary.

  • Page 29: Cooling System

    RX SX 125 Maintenance Cooling system Level check Check and top-up CAUTION WAIT FOR THE ENGINE TO COOL DOWN BEFORE CHECKING OR TOPPING-UP THE COOLANT LEVEL. • Shut off the engine and wait until it cools off. • Park the vehicle on firm and level ground.
  • Page 30 RX SX 125 Maintenance Top-up • The following operations refer to one braking system but they are valid for both braking systems: 1. Front brake fluid reservoir (1); 2. Rear brake fluid reservoir (2). CAUTION RISK OF BRAKE FLUID SPILLS. DO NOT PULL THE...

  • Page 31: Clutch System

    RX SX 125 Maintenance • Top-up the reservoir you are working with (1 or 2) until the level goes over the minimum marked MIN. CAUTION TOP-UP TO MAXIMUM LEVEL MARK ONLY WHEN BRAKE PADS ARE NEW. BRAKE FLUID LEV- EL DECREASES GRADUALLY AS BRAKE PADS WEAR OUT.
  • Page 32 RX SX 125 Maintenance • Tighten (unscrew) the nut (3), locking the set screw (1). • Check the empty travel at the clutch lever end. • Refit he protection casing (2). • If the set screw (1) is fully screwed, fully...

  • Page 33: Headlight Adjustment

    RX SX 125 Maintenance CHECK THE CLUTCH CONTROL CABLE IS IN GOOD CON- DITIONS: THERE SHOULD BE NO SIGNS OF CRUSHING OR WEAR ALL ALONG THE SHEATH. • Lubricate the clutch wire frequently with an appropriate grease to avoid early wear and cor- rosion.
  • Page 34 INDEX OF TOPICS TROUBL ROUBLESHOOTING...
  • Page 35 RX SX 125 Troubleshooting CAUTION IF THERE IS ANY ENGINE FAILURE, THE CONTROL UNIT DOES NOT TURN ON THE EFI WARNING LIGHT. THE EFI WARNING LIGHT IS INACTIVE IN THIS VEHICLE. THE OPERATOR WHO ENCOUNTERS A FAILURE IN THE ENGINE MUST CARRY OUT ALL THE PRESCRIBED AX- ONE CHECKS WITH THE AIM OF ENSURING THE ENGINE HAS BEEN THOROUGHLY CHECKED.
  • Page 36 INDEX OF TOPICS ELE SYS LECTRICAL SYSTEM...
  • Page 37 RX SX 125 Electrical system Components arrangement ELE SYS - 37...
  • Page 38 RX SX 125 Electrical system Components - Key (RX/SX 125): 1. Front headlamp 2. Coil 3. fuses 4. Battery 5. Turn indicators 6. Voltage regulator ELE SYS - 38...
  • Page 39 RX SX 125 Electrical system 7. Rear light 8. Right rear turn indicator 9. Speed sensor 10.STARTER MOTOR 11.Neutral sensor 12.Pick-up sensor 13.Intake air valve (MAJ2) 14.Spark plug 15.Left front turn indicator 16.Mixer oil level sensor 17.CDI control unit 18.Coolant temperature thermistor 19.Instrument panel...
  • Page 40 RX SX 125 Electrical system • Instrument panel connector • Pick Up connector • Regulator connector • Control unit connectors • Ground eyelets • Key switch connector • Left Light Switch Connector The connectors listed (indicated with a green dot on the photo) are considered the most critical of all because a possible disconnection may cause the motorcycle to stop.
  • Page 41 RX SX 125 Electrical system TABLE B - ENGINE AND CARBURETTOR 4. Faston Horn 5. Horn TABLE C - FRONT 6. Metallic clamp 7. Left light switch connector TABLE D - FRONT 8. Instrument panel connector 9. Key switch connector 10.
  • Page 42 RX SX 125 Electrical system TABLE F - FRONT • Headlight cable harness • Place the cable harness in the front inner part. ELE SYS - 42...
  • Page 43 RX SX 125 Electrical system Central part TABLE A - MAIN CABLE HARNESS LAYING • Metallic clamp TABLE B - FILTER CASING AND CONTROL UNIT 1. Air temperature sensor connector 2. Clamp 3. Regulator connector TABLE B - FILTER CASING AND CONTROL UNIT 4.
  • Page 44 RX SX 125 Electrical system TABLE E - FILTER CASING AND CONTROL UNIT 13. ECU 1 connector 14. ECU 2 connector 15. Oil reserve connector 16. Diagnosis connector TABLE F - ENGINE AND CARBURETTOR • Heater connector TABLE G - ENGINE AND CARBURETTOR •...
  • Page 45 RX SX 125 Electrical system TABLE I - SADDLE PILLAR 23. Cable harness laying 24. Ground eyelets 25. Clamps TABLE J - GROUND LEAD FITTING 26. Ground eyelets 27. Faston coil 28. Ground lead 29. Coil ELE SYS - 45...
  • Page 46 RX SX 125 Electrical system Back side TABLE A - SADDLE PILLAR 1. Rear left arrow connector 2. Rear headlight connector 3. License plate connector 4. Rear right arrow connector 5. Clamp 6. Cable harness laying TABLE B - LICENSE PLATE HOLDER PRE-FITTING 7.
  • Page 47 RX SX 125 Electrical system TABLE C - LICENSE PLATE HOLDER PRE-FITTING ELE SYS - 47...
  • Page 48 RX SX 125 Electrical system TABLE D - SPEED SENSOR 12. Cable harness passes together with brake pipe 13. Cable harness passes together with brake pipe 14. Clamp ELE SYS - 48...
  • Page 49 RX SX 125 Electrical system General wiring diagram Components key : 1. MULTIPLE CONNECTORS 2. ECU DIAGNOSIS 3. AIR TEMPERATURE SENSOR 4. ELECTRONIC INSTRUMENT PANEL ELE SYS - 49...
  • Page 50 RX SX 125 Electrical system 5. LOW OIL SENSOR 6. TURN INDICATORS 7. LEFT LIGHT SWITCH 8. KEY SWITCH 9. HORN 10.REAR LEFT TURN INDICATOR 11.REAR LIGHT 12.LICENSE PLATE LIGHT 13.REAR RIGHT TURN INDICATOR 14.FUSES 15.FRONT STOP SWITCH 16.REAR STOP SWITCH 17.BATTERY...
  • Page 51 RX SX 125 Electrical system R red Ro pink V green Vi purple CDI Control unit pinout: 1. RAVE VALVE 2. K LINE 3. + LIVE 4. TEMPERATURE SENSOR 5. +5V TPS 6. MIL BULB 7. MAJ2 VALVE 8. SPEED OUT 9.
  • Page 52 RX SX 125 Electrical system 15.- 16.- 17.- 18.EFI WARNING LIGHT Checks and inspections Dashboard To change the setting from km/h to Mph or vice versa: • hold down the MODE button when in- serting the key until WS is displayed in...
  • Page 53 RX SX 125 Electrical system • To exit, turn the key to OFF. CONFIGURATION OF WHEEL SIZE ON IN- STRUMENT PANEL The first time the RX125 - SX125 instrument panel is switched on, it must be configured according to the correct wheel size.
  • Page 54 MODE button and 0001 or 0002 is displayed • press the MODE button again to change from 0001 (SX 125 17 wheel) to 0002 (RX 125 18 wheel) and vice versa. Hold down the MODE button to confirm and WS will be displayed •...
  • Page 55 RX SX 125 Electrical system • Press the MODE switch fast until the service icon (Wrench symbol) is dis- played. The words km/h - Mph and OIL word are displayed first. • Hold down the MODE button until the dashes ---- are displayed. Once the key is released, the words NO CLEAR will be displayed.
  • Page 56 RX SX 125 Electrical system Ignition circuit Key: 1. Instrument panel 2. Key switch 3. Battery 4. fuses 5. CDI control unit ELE SYS - 56...
  • Page 57 RX SX 125 Electrical system Characteristic Standard spark plug NGK BR8ES Standard spark plug (FULL POWER) NGK R BR10ES Electrode gap 0.7 - 0.8 mm (0.027 - 0.031 in) Troubleshooting • Check that the 7.5 A fuse and 20 A fuse are not damaged.
  • Page 58 RX SX 125 Electrical system 1. Instrument panel 2. Key switch 3. fuses 4. Battery 5. Voltage regulator 6. Generator Recharge check • Start the engine and make it run at 6000 rpm. • Connect a tester in voltmeter function to check the direct current on the battery leads.
  • Page 59 RX SX 125 Electrical system Voltage regulator check • Output voltage 13.5 V - 15 V • Output current higher than 10 A (with load) Turn signals system check Turn indicator device check Check placing the tester probes on the poles: + / - 5.8 kOhm.
  • Page 60 RX SX 125 Electrical system Horn control Testing voltage: 13 V (nominal 12 V) Input: < 3.5 A With a tester in ohmmeter function check the con- tinuity of the contacts as per the diagram below. Diode check • Disconnect the two-way connector (white).
  • Page 61 RX SX 125 Electrical system Lights list Key: 1. Instrument panel 2. Horn 3. Diode 4. Left rear turn indicator ELE SYS - 61...
  • Page 62 RX SX 125 Electrical system 5. Rear light assembly 6. License plate light bulb 7. Right rear turn indicator 8. Front stop switch 9. Rear stop switch 10.fuses 11.Right front turn indicator 12.Front headlamp 13.Left front turn indicator Troubleshooting: •...

  • Page 63: Control Unit

    RX SX 125 Electrical system BULBS BULBS SX 125 RX 125 License plate bulb Rear tail light /stop light Front tail bulb 2V x 3W 2V x 3W Front/rear turn indicator bulbs 4 x 10W 4 x 10W Low-/high-beam light bulb...

  • Page 64: Speed Sensor

    RX SX 125 Electrical system Battery BATTERY (12 V - B9 - B) (12 V - 4 A) In case of malfunction check first that the recharge system works properly. To check the battery, remove it from the vehicle, and proceed as follows; visually check that : - there are no signs of sulphation (signalled by white colouring of one or more cells);...
  • Page 65 RX SX 125 Electrical system Engine rpm sensor Pick-up check • Disconnect the connector of the pick- up terminals. • With a pocket tester (1000 Ohm scale) measure the resistance between the terminals of the yellow/blue and yellow/ white cables. The resistance value measured should be between 190 and 300 Ohm.
  • Page 66 RX SX 125 Electrical system Air intake valve Air valve resistance 70 - 80 OHM at 25 °C (77 °F) Not powered: closed valve Powered with 12V: open valve Coil Coil winding resistance Primary 0.11 - 0.21 Ohm. Secondary 4.3 - 8.1 kOhm Checking Use a pocket tester to check the coil.
  • Page 67 RX SX 125 Electrical system Neutral sensor Check the values with a tester: - With the gear engaged, the tester indicates an infinite resistance value. - In neutral position, resistance is equal to 0 Ohm. Connectors ONNECTOR Specification Desc./Quantity Pin 1...
  • Page 68 RX SX 125 Electrical system Dashboard Instrument panel pinout: 1. LEFT INDICATORS INPUT 2. RIGHT INDICATORS INPUT 3. NEUTRAL INPUT 4. INPUT FOR HIGH-BEAM LIGHTS 5. SPEED SENSOR INPUT 6. - 7. OIL LEVEL SENSOR 8. - 9. - 10.- 11.+ LIVE...
  • Page 69 INDEX OF TOPICS ENG VE NGINE FROM VEHICLE...
  • Page 70 RX SX 125 Engine from vehicle Vehicle preparation CAUTION BEFORE CARRYING OUT THE OPERATIONS BELOW, BEAR IN MIND THAT THE ENGINE MUST BE REMOVED FROM THE CHASSIS TOWARDS THE BOTTOM; AFTERWARDS ARRANGE AND POSITION THE NECESSARY TOOLS. NOTE GET A HOIST AND BELTS FOR LIFTING.
  • Page 71 RX SX 125 Engine from vehicle • Disconnect the oil pipes and cover them. • Undo and remove the three screws and remove the oil pump cover. • Loosen the set nut. • Slide off the throttle cable from the oil pump.
  • Page 72 RX SX 125 Engine from vehicle • Slide off the mixer oil pipe. • Cover the tank outlet and pipe. • Disconnect the spark plug tube. • Disconnect the thermistor electric con- nector. • Loosen the locking washer completely (2).
  • Page 73 RX SX 125 Engine from vehicle • Unscrew and remove the gearbox oil filler cap. • With a small plain slot screwdriver, re- move the clutch cable from its seat . • Slide off the clutch cable. CAUTION UPON REFITTING CHECK THE CLUTCH LEVER CLEAR- ANCE.
  • Page 74 RX SX 125 Engine from vehicle • Undo and remove the two screws fixing the pinion protection cover and then remove it. CAUTION TO FACILITATE SLIDING OFF THE TRANSMISSION PIN- ION, SLIGHTLY LOOSEN THE DRIVE CHAIN. • Remove the Seeger ring.
  • Page 75 RX SX 125 Engine from vehicle • Working from the left side of the vehi- cle, undo the screw while keeping the right-hand side nut tightened. • Release the engine temperature sen- sor. ENG VE - 75...
  • Page 76 RX SX 125 Engine from vehicle • Disconnect the connections. • Remove the pipe from the hose guide. • Remove the carburettor. ENG VE - 76...
  • Page 77 RX SX 125 Engine from vehicle • Remove the clamp and disconnect the secondary air pipe. • Undo and remove the screw discon- necting the connectors of the system ground connections. • Undo and remove the screw and dis- connect the speed sensor.
  • Page 78 RX SX 125 Engine from vehicle • Remove the front screw that fixes the engine to the chassis and collect the nut on the right-hand side of the vehi- cle. • Working from the right side and using the suitable swingarm pin adjustment tool, fully loosen the ring nut (5).
  • Page 79 RX SX 125 Engine from vehicle • Insert the front screw that fixes the en- gine to the chassis and fasten the nut. • Place the swingarm on the chassis. • Move it into position so that the holes are aligned and, at the same time, in- sert the pin fully from the left side.
  • Page 80 RX SX 125 Engine from vehicle - Tighten the ring nut (1) using an adequate special tool. - Tighten the swingarm pin. • Fit the speed sensor and tighten the screw. • Fit the carburettor. • Replace the clamp and connect the secondary air pipe.
  • Page 81 RX SX 125 Engine from vehicle - System ground connections, tighten the screw. - Connect the neutral gear sensor. • Replace the clamps. ENG VE - 81...
  • Page 82 RX SX 125 Engine from vehicle - Control unit ground connection. - Pick-up - Generator. • Connect the engine temperature sen- sor connector. ENG VE - 82...
  • Page 83 RX SX 125 Engine from vehicle • Fit the transmission pinion with the chain on the shaft. • Fit the Seeger ring. • Fit the pinion protection case and fix it by means of two screws. • Place the oil pipes on the engine crank- case fastening them with the hose guides.
  • Page 84 RX SX 125 Engine from vehicle • Install the battery. • Replace the clamp and connect the ex- pansion tank pipe. • Reposition the clutch cable in its seat. • Tighten the gearbox oil filler cap. • Fit the clutch cable (3) in the clutch lev- •...
  • Page 85 RX SX 125 Engine from vehicle • Connect the thermistor electric con- nector. • Connect the spark plug tube. • Place the throttle cable in the oil pump. • Adjust the throttle cable tension by op- erating the nut on the oil pump until it is aligned with the two references.
  • Page 86 RX SX 125 Engine from vehicle • Position the oil pump cover and tighten the three screws . • Place the cooling system pipes, re- place the clamps. • Make sure all engine fixing screws / locking nuts are tightened to the prescribed torque.
  • Page 87 RX SX 125 Engine from vehicle CAUTION AVOID TWISTING AND CRUSHING CABLES. • the electrical connectors are correctly coupled; • the pipes and unions are correctly fitted and secured with suitable clamps; • the throttle and cold start cables slide freely and do not cause the handlebar to rotate.
  • Page 88 INDEX OF TOPICS NGINE...
  • Page 89 RX SX 125 Engine Gearbox Gearbox shafts Disassembling the gearbox • Open the crankcase halves. • Remove the gaskets from the crank- case. • Take out the countershaft. • Fix the flywheel-side crankcase half on the engine support with the adequate screw and spacer.
  • Page 90 RX SX 125 Engine • Unscrew and remove the desmodrom- ic control fixing screw and collect the washer. • Slide off the three gear forks from the guides of the desmodromic drum con- trol. • Remove the desmodromic drum con- trol.
  • Page 91 RX SX 125 Engine • Rotate the crankcase half on the sup- port to the standard position. • Remove gearbox unit (primary + sec- ondary). Checking the primary shaft • Check the state of the joints and grooves. Max. admissible deviation (A) 0.03 mm (0.0012 in);...
  • Page 92 RX SX 125 Engine • The lever roller (6) must rotate freely. • Check that the stop tab (7) and the rel- evant spring (8) work properly. • Check that the gear shaft is not de- formed. (A) Max. admissible deviation = 0.15 mm (0.0059 in);...
  • Page 93 RX SX 125 Engine • Apply oil for gears on the grooves of the desmodromic drum. • Fit the desmodromic in the crankcase. • Fit the washer and the desmodromic control fixing screw and tighten them. • Insert all the forks in the desmodromic guides.

  • Page 94: Starter Motor

    RX SX 125 Engine Starter motor STARTER MOTOR • Make sure that the toothing (1) is not deformed or worn. • Make sure that the O-ring (2) is not damaged or worn. • The electric starter motor is not fitted for repair.
  • Page 95 RX SX 125 Engine Removing the idle gear • Remove the magneto flywheel. • Slide off the starter motor gear. See also Magneto flywheel removal Fitting the idle gear • Rotate the engine support so that it faces upwards, flywheel side.
  • Page 96 RX SX 125 Engine • Remove the flywheel cover. Magneto flywheel removal • Remove the flywheel cover. • Remove the starter motor gear cover. • Undo the two M5 screws and remove the external "pick up". ENG - 96...
  • Page 97 RX SX 125 Engine • Place the extractor plate on the fly- wheel and fix it with the three M6 Allen screws. The flywheel cam must be fac- ing the external "pick up", making sure that the crankshaft is at TDC When...
  • Page 98 RX SX 125 Engine • Fit the protection sleeve on the crank- shaft thread. • Insert the long threaded end of the ex- tractor screw in the extractor plate and remove the flywheel. Removing the stator • Undo and remove the three M6 stator fixing screws.
  • Page 99 RX SX 125 Engine • Place the extractor plate correctly with the locking bolts on the flywheel and fix it with three screws (M6 x 16). Specific tooling AP0277455 Extractor plate to separate the crankcase halves • Tighten the magneto flywheel fixing nut.

  • Page 100: Stator Installation

    RX SX 125 Engine • Apply SILASTIC 732 RTV to the cable guide of coil and stator, then slide it in the crankcase hollow space. • Fit the electric starter device cover on the starter gear. Stator installation • Insert the woodruff key in the crank- shaft.
  • Page 101 RX SX 125 Engine • Tighten the six flywheel cover fixing screws. Clutch side Removing the clutch cover • Undo and remove the nine screws fix- ing the clutch cover. • Lift the clutch cover using two screw- drivers as levers at the prearranged...

  • Page 102: Checking The Clutch Plates

    RX SX 125 Engine Disassembling the clutch • Remove the pack of the clutch discs from the clutch base. • Remove the clutch base of the secon- dary shaft. Checking the clutch plates • Undo and remove the six M5 fixing screws (9) crosswise and remove the clutch.
  • Page 103 RX SX 125 Engine • Cage and rollers of both needle bearings (3). • Internal disc (4) toothing. • Friction discs (5) for damage. • Internal clutch discs (6) for damage, scores or wear • The locking disc ball (7) must move freely and must not be worn.
  • Page 104 RX SX 125 Engine Checking the clutch hub • When the clutch hub is worn, this may cause bell sliding problems. Replace the hub if its surface has exceeded the wear limit. Max. wear limit (A) 0.3 mm (0.012 in).

  • Page 105: Removing The Cylinder Head

    RX SX 125 Engine Removing the head cover • Undo and remove the four Allen screws fixing the head cover. • Remove the head cover. • Remove both O-rings. Removing the cylinder head • Remove the head cover. • Remove the five M8 Allen screws and the locking washers.
  • Page 106 RX SX 125 Engine • The seal surface of the combustion chamber insert gets slightly conic start- ing from a 63 mm (2.48 in) diameter. CYLINDER HEAD COVER • Make sure the seal surfaces of the two O-rings are clean.
  • Page 107 RX SX 125 Engine Disassembling the piston • Remove the cylinder. • Remove one of the two seeger rings of the pin using a suitable tool. CAUTION BEFORE TAKING OUT THE PIN SEEGER RING, COVER THE CRANKCASE OPENING WITH A CLOTH SO THAT THE RING DOES NOT FALL INTO THE CRANKCASE.
  • Page 108 RX SX 125 Engine Checking the cylinder • Remove any scales formed by water in the cooling interspace on the cylinder (A). • Clean off any combustion deposits from the outlet port (B). • Clean and check the groove of the O- ring (C).
  • Page 109 RX SX 125 Engine • The pin (2) should adjusted to the pis- ton without considerable clearance. • Make sure the grooves of the seeger rings (4) are not worn. • Measure the axial clearance of the rings with a thickness gauge; max.
  • Page 110 RX SX 125 Engine • Apply engine oil on the lubrication ducts for the main bearings of the crankshaft, on the head bearings and on the rod small ends. • Make the ball retainer slide on the con- necting rod.
  • Page 111 RX SX 125 Engine • Place the cylinder. ONLY ASSEMBLE TOGETHER PISTONS AND CYLINDERS BELONGING TO THE SAME TOLERANCE RANGES. • Take out the wrench for piston rings. • Working from both sides, fasten the cylinder crosswise with the four M8 nuts and relevant washers.

  • Page 112: Installing The Cylinder Head

    RX SX 125 Engine The piston nominal size is stamped on the piston crown. Pistons are grouped in types according to their sizes: • PISTON "A"; Piston diam. = 53.98 mm (2.1252 in), wear limit = 53.93 (2.1232 in), matching cylinder: "A"...
  • Page 113 RX SX 125 Engine Installing the head cover • Fit the O-rings. • Fit the head cover already fitted with the thermostat. • Tighten crosswise the four screws fix- ing the head cover. Crankcase - crankshaft Splitting the crankcase halves •...
  • Page 114 RX SX 125 Engine • Remove the control gear from the crankshaft. • Remove the two countershaft gears with a suitable tool. • Remove the gear shaft and collect the thrust washer. ENG - 114...
  • Page 115 RX SX 125 Engine • Undo and remove the screw fixing the lever. • Remove the lever and collect the spring, the spacer and the washer. • Undo and remove the nine screws fix- ing the crankcase halves. • Undo and remove the support screw.
  • Page 116 RX SX 125 Engine • Place the extractor plate. • Fit the three fixing screws. • Adequately centre the plate with refer- ence to the crankshaft. • Tighten the three fixing screws. • Screw the long threaded end of the ex-...
  • Page 117 RX SX 125 Engine • Place the extractor plate and fix it with four M6 fixing screws, but do not fully tighten them. • Adequately centre the tool. • Tighten the four M6 fixing screws. • Insert the extractor screw with the long threaded end in the extractor plate.
  • Page 118 RX SX 125 Engine • Check that all ball bearings move smoothly and are not worn. When replacing the ball bear- ings, check the negative allowance in the crankcase. Min. ALLOWANCE = 0.010 mm (0.00039 in). ONLY THE BALL BEARING SEATS OF THE DESMODROMIC DRUM ARE SLIDING.
  • Page 119 RX SX 125 Engine • Insert the oil seal (8) of the main shaft from the inside to the outside using a punch for fitting. Specific tooling AP0276502 Buffer for fitting oil seal 930675 • Push the ball bearing (7) of the main shaft using a suitable punch.
  • Page 120 RX SX 125 Engine • In order to refit the oil seal (12) of the crankshaft, push it into position from the outside to the inside with a punch for fitting (14). THE OIL SEAL EDGE SHOULD BE FACING OUTWARDS.
  • Page 121 RX SX 125 Engine Checking the counter shaft • Check countershaft for wear: (1) Fly- wheel side bearing seat, Minimum wear limit diameter: 14.94 mm (0.5882 in) ; (2) Clutch side bearing seat, Mini- mum wear limit diameter: 24.94 mm (0.9819 in) ;...
  • Page 122 RX SX 125 Engine NEVER TAP THE CRANKSHAFT UNIT WITH A MALLET TO FIT IT INTO THE CRANKCASE. Specific tooling AP0277917 Brackets IF THE CRANKCASE, THE CRANKSHAFT OF THE MAIN BEARING ON THE CRANKSHAFT HAVE BEEN REPLACED, THE AXIAL CLEARANCE OF THE SHAFT NEEDS TO BE READJUSTED.
  • Page 123 RX SX 125 Engine Refitting the crankcase halves • Unscrew and remove the fixing bolt and the washer from the support. • Apply LOCTITE Anti-Seize to each bearing seat of the shafts. • Fit the crankcase gasket on the flywheel-side crankcase half.
  • Page 124 RX SX 125 Engine • Insert the gear shaft pre-assembled in the crankcase. SET THE GEAR TO IDLE AND MAKE SURE BOTH THE SECONDARY AND THE MAIN SHAFTS MOVE SMOOTHLY. ENGAGE 3rd GEAR AND TURN THE SHAFT TO LEFT AND RIGHT UNTIL THE LATCH TOUCHES THE RELEVANT PIN ON THE DESMODROMIC DRUM.

  • Page 125: Oil Pump

    RX SX 125 Engine • Fit the crankshaft control gear. • Fit the locking seeger ring of the crank- shaft control and that of the counter- shaft control. NEVER REUSE OLD SEEGER RINGS. WHEN USING A SEEGER RING, BE CAREFUL NOT TO OVER STRETCH IT.
  • Page 126 RX SX 125 Engine Removing • Place the engine support so as to fa- cilitate oil pump removal operations. • Undo and remove the two screws fixing the oil pump. • Remove the oil pump and the O-ring underneath; collect the oil pipes and their guides.
  • Page 127 RX SX 125 Engine • Before riding the bike for the first time; • Each time the engine has been operating with an empty oil reservoir; • When the lubrication system components have been replaced. In order to bleed the oil pump and pipes, open the oil bleed screw (5).
  • Page 128 RX SX 125 Engine ing of the exhaust fumes that might cause bursts in the muffler which may damage the exhaust valves and the catalytic converter. WHEN ADJUSTING CO DEACTIVATE THE SECONDARY AIR SYSTEM AS THE EXHAUST FUMES DILUTED BY THE SYSTEM DISTORT THE READING OF THE CARBON MON- OXIDE PERCENTAGE.
  • Page 129 INDEX OF TOPICS P SUPP OWER SUPPLY...
  • Page 130 RX SX 125 Power supply Circuit diagram Key: 1. Fuel tank 2. Fuel cock 3. Oil mixer tank 4. Oil reservoir cap 5. Oil level gauge Carburettor Removing • Remove the fuel tank. • Undo the two screws. P SUPP - 130...
  • Page 131 RX SX 125 Power supply • Remove the throttle valve but keep it connected to the throttle cable. • Remove the screw. • Remove the cold start control but keep it connected to the cable. • Disconnect connectors (1) and (2).
  • Page 132 RX SX 125 Power supply • Working from the right side, remove the fuel pump (3) vacuum hose and the fuel hose (4). • Loosen the clamps. P SUPP - 132...
  • Page 133 RX SX 125 Power supply • Remove the clamp and slide off the fil- ter casing pipe. • Choke the mix oil hose with a clamp and remove from the carburettor. • Rotate carburettor to the left. • Remove the carburettor.
  • Page 134 RX SX 125 Power supply Disassembling Removing the carburettor • Remove the two screws and slide off the throttle valve / throttle valve posi- tion sensor unit. • Remove the heater. • Remove the float chamber cap. • Remove the maximum nozzle cap.
  • Page 135 RX SX 125 Power supply • Remove the minimum nozzle. • Remove the start-up nozzle. • Remove the throttle valve position sen- sor. Carburettor refitting • Make sure that the TPS gear (5) is fully turned clockwise; the control arm (6) should be at the fully extended posi- tion.
  • Page 136 RX SX 125 Power supply • Assemble the sensor with the fixing eyelet to the left compared with the cor- rect fixing position. • Turn the sensor clockwise until the eyelets are aligned and fix the position with the corresponding screw.
  • Page 137 RX SX 125 Power supply Engine parameter screen page ENGINE PARAMETER READING Specification Desc./Quantity Engine revs rpm, measured with crankshaft rpm detection sensor Throttle valve opening %, indication ranges from 0 to 100 % Air temperature 23 °C, if signal is lost, the control unit set the value to 50 °C...
  • Page 138 RX SX 125 Power supply Specification Desc./Quantity Supply voltage tool low. Below the minimum level Voltage below 10 V, longer than 10 seconds has been detected at pin 3 of the large connector in the control unit Supply voltage tool high. Over the maximum level Voltage over 15.5 V, longer than 20 seconds has been detected...
  • Page 139 INDEX OF TOPICS SUSP USPENSIONS...
  • Page 140 RX SX 125 Suspensions Front Key: 1. Tyre 2. Air chamber 3. Wheel flap 4. Nipples 5. Rim 6. Front wheel radius 7. Front wheel radius 8. Front wheel radius 9. Front wheel radius 10.Hub 11.Wheel spacer 12.Bearings spacer 13.Hub bearing 14.Oil seal...

  • Page 141: Removing The Front Wheel

    RX SX 125 Suspensions 19.Seeger ring 20.Front hub pin Removing the front wheel CAUTION UPON REMOVING, PAY ATTENTION NOT TO DAMAGE THE BRAKE HOSES, DISCS AND PADS. • Place the vehicle on its OPTIONAL rear service stand. CAUTION MAKE SURE THE VEHICLE IS STABLE.
  • Page 142 RX SX 125 Suspensions • Place a stand under the tyre to keep the wheel in position once it is free. • Slide off the wheel pin from the left side. • Collect the spacer from the left side. •...

  • Page 143: Installing The Front Wheel

    RX SX 125 Suspensions WHEEL PIN Using a dial gauge, check the wheel pin eccen- tricity. If the eccentricity exceeds the limit value, replace the pin. Maximum eccentricity: 0.25 mm (0.0098 in) Using a dial gauge, check that the radial (A) and the axial (B) eccentricities of the rim do not exceed the limit value.
  • Page 144 RX SX 125 Suspensions • Move the wheel until the central hole is aligned with the holes on the wheel. • Working from the left side, insert the wheel bolt until it stops. • Finger tighten the cap. • Lock the wheel pin so that it does not rotate.

  • Page 145: Front Fork

    RX SX 125 Suspensions • Remove the (OPTIONAL) front service stand. • Remove the (OPTIONAL) rear service stand. CAUTION AFTER REFITTING, OPERATE THE FRONT BRAKE LEVER REPEATEDLY AND CHECK THAT THE BRAKING SYSTEM OPERATES CORRECTLY. CAUTION AFTER REFITTING, PULL THE BRAKE LEVER REPEATEDLY AND CHECK THAT THE BRAKING SYSTEM OPERATES CORRECTLY.

  • Page 146: Removing The Fork Legs

    RX SX 125 Suspensions 8. Dust guard with clip 9. Spacer 10.Nut 11.Spring guide 12.Snap ring 13.Right pumping member rod 14.Right pumping member 15.Pin 16.Spring 17.Cap 18.Ring 19.Spring 20.Piston ring 21.Piston 22.Nut 23.Valve 24.Sliding bushing 25.Left pumping member rod 26.Left pumping member 27.Cap...
  • Page 147 RX SX 125 Suspensions THE FOLLOWING OPERATIONS REFER TO A SINGLE STEM BUT APPLY TO BOTH. • Undo both locking screws of the lock clamp placed on the brake pipe on left stem protection. • Release the brake pipe from the left stem protection.
  • Page 148 RX SX 125 Suspensions • Slide off the stem downwards, being careful not to damage its surface. Draining oil CAUTION THE FOLLOWING OPERATIONS REFER TO A SINGLE WHEEL HOLDER STEM / SLEEVE BUT APPLY TO BOTH. • Remove the wheel holder stem / sleeve unit.
  • Page 149 RX SX 125 Suspensions • Remove the spring preloading pipe. • Remove the spring. • Drain the oil off the stem being careful not to slide the stem sleeve. • For easy drainage of the oil inside the cartridge, pump it several times with the stem in vertical position.
  • Page 150 RX SX 125 Suspensions • Drain again all the oil inside the stem. Disassembling the fork CAUTION THE FOLLOWING OPERATIONS REFER TO A SINGLE WHEEL HOLDER STEM / SLEEVE BUT APPLY TO BOTH. • Screw the stem, on the foot side, with a vice fitted with protection jaws to avoid damaging it.
  • Page 151 RX SX 125 Suspensions • Remove the snap ring inside the sleeve using a thin screwdriver. • With a thick plain slot screwdriver re- move the sealing ring from its seat carefully and operate at several points in one third of its circumference without damaging the oil seal and the sleeve rim.
  • Page 152 RX SX 125 Suspensions • Screw the stem, on the foot side, with a vice fitted with protection shoes that avoid damaging it. • With the cartridge rod firmly in place, unscrew and remove the bottom screw and its gasket.
  • Page 153 RX SX 125 Suspensions • Check the sliding surface for scorings and/or scratches. These scorings can be eliminated by rubbing them with wet sandpaper (grain 1). • If the scorings are deep, replace the stem. • Use a dial gauge to check that the stem bending is below the limit value.
  • Page 154 RX SX 125 Suspensions • Insert the sliding bushing (1), use the spacer (2) to push it into the sleeve. • Then fit another sliding bushing (3); if required, use a buffer of suitable diam- eter to push in into the sleeve.
  • Page 155 RX SX 125 Suspensions • Lubricate the dust guard (6) and the oil seal (5) with a layer of oil . • Insert on the fork stem: the dust guard (6), the snap ring (7), the oil seal (5) and the guide bushing cap (4).
  • Page 156 RX SX 125 Suspensions • Place the stem cover guide in the sleeve and tighten the fixing screw. Filling oil • Place the sleeve upright in a vice fitted with protection jaws. • Compress the sleeve in the stem. Place a support under the stem in order to leave it compressed.
  • Page 157 RX SX 125 Suspensions • Take the pumping member rod fully out of the sleeve cartridge. • Insert the spring keeping the pumping member rod in place. • Insert an open key under the lock nut to support the pumping member rod and the spring.

  • Page 158: Installing The Fork Legs

    RX SX 125 Suspensions Installing the fork legs • Insert the sleeve together with the wheel holder stem on the lower and upper plates. • Insert the wheel pin through both stems to align the holes. • Tighten the screw that locks the lower plate to the sleeve.
  • Page 159 RX SX 125 Suspensions • Slide off the wheel pin. • Mount the front wheel. • Fit the front brake calliper and tighten the two fixing screws. Steering bearing Key: 1. Headstock cap 2. Washer SUSP - 159...
  • Page 160 RX SX 125 Suspensions 3. Dust guard 4. Dust guard support ring 5. Roller bearing 6. Sealing ring 7. TE screw 8. Washer 9. Fork upper plate 10.Fork lower ring nut 11.Base with headstock 12.TCE screw 13.Screw 14.U-bolt Adjusting play •...
  • Page 161 RX SX 125 Suspensions • Undo and remove the screw. • Operating on both sides, loosen the screw. • Fully loosen the ring nut with a crescent type wrench. Afterwards, tighten the ring nut again to the prescribed torque, restoring the clearance.
  • Page 162 RX SX 125 Suspensions • Screw and tighten the two screws. CAUTION ONCE THE OPERATION IS FINISHED, MAKE SURE THE HANDLEBAR ROTATES SMOOTHLY TO AVOID DAMAG- ING THE SLIDING GUIDES AND COMPROMISING VEHI- CLE HANDLING. Rear Key: 1. Rear tyre 2.

  • Page 163: Removing The Rear Wheel

    RX SX 125 Suspensions 11.Seeger ring 12.Oil seal 13.Rear wheel pin 14.Low self-locking nut 15.Washer 16.Rear wheel spacer 17.Crown 18.Low self-locking nut 19.Curved spring washer 20.TSPEI screw 21.Chain with master link 22.Bare rear wheel 23.Bearings spacer 24.Hub bearing Removing the rear wheel •...

  • Page 164: Checking The Rear Wheel

    RX SX 125 Suspensions • Working in both sides, loosen the set screw. • Slide off the chain. • Collect the chain tensioner • Use a rubber hammer to slide off the wheel bolt from the vehicle left side; collect the centring shim washers and slide off the wheel backwards.

  • Page 165: Installing The Rear Wheel

    RX SX 125 Suspensions Insert the anti-vibration buffer in the wheel hub. Fit the entire final transmission unit on the wheel, manually rotate the crown gear to right and left and check the clearance between the anti-vibration buffer and the hub. Replace the anti-vibration buffer if excessive clearance is found.

  • Page 166: Shock Absorbers

    RX SX 125 Suspensions Shock absorbers 1. Shock absorber 2. Single connection rod 3. Double connecting rod 4. TCEI M10x55 screw 5. 10.5x21x2 washer 6. M10 Flanged self-locking nut 7. TE flanged M10x61 screw 8. D18x24x3 oil seal 9. Roller casing 10.L=36 pin...
  • Page 167 RX SX 125 Suspensions 13.12.2x22x2 Plain iron washer 14.M12 lower self-locking nut 15.TE flanged screw M6x20 16.Bushing 17.Clip M6 Adjusting The rear shock absorber standard setting is adjusted to suit most low speed riding conditions, whether the vehicle is partially or fully loaded.
  • Page 168 RX SX 125 Suspensions Removing • Place the vehicle on its OPTIONAL front service stand. • Remove both central side fairings. • Support the vehicle rear part using belts and hoist. • Place a support between the swingarm and the saddle post frame so that the shock absorber is in neutral position.
  • Page 169 RX SX 125 Suspensions Installing SHOCK ABSORBER FITTING • Fit the shock absorber by inserting from the bottom. • Insert the shock absorber upper screw with the washer from the left side. • Working from the opposite side, tighten the nut (1).
  • Page 170 RX SX 125 Suspensions Removing • Working from the right side, unscrew and remove the nut (1). • Slide off the screw from the opposite side and collect the washer. • Working from the left side, unscrew and remove the nut (2).
  • Page 171 RX SX 125 Suspensions • Remove the oil seals (7) from the dou- ble connecting rod. • Slide off the pin (8). • Using a specific extractor, take out the ball retainer (9). • Remove the belleville spring (10). •...
  • Page 172 INDEX OF TOPICS CHAS HASSIS...
  • Page 173 RX SX 125 Chassis Swinging arm 1. Swingarm 2. Chain guard 3. Chain guide slider 4. Slider cap 5. TCB M4.8x13 screw 6. Swing arm pin 7. 22x28x16 Roller casing 8. Sealing ring 9. D15x22x1 knurled washer 10.M14x1.5 lower nut 11.Swing arm pin bushing...
  • Page 174 RX SX 125 Chassis 12.Thrust washer 13.grey rear chain guide 14.TE flanged screw M6x20 15.T-shaped bushing 16.M6 lower self-locking nut 17.Rh chain tensioner 18.Lh chain tensioner 19.Chain tensioner set screw 20.M8 lower nut 21.TBEI flanged M5x12 screw Removing CAUTION HOLD THE VEHICLE STEADY WITH THE OPTIONAL SERVICE STAND FROM THE FRONT AND BELTS ATTACHED TO AN OPTIONAL HOIST FROM THE REAR.
  • Page 175 RX SX 125 Chassis • Undo and remove the external screw (3). • Detach the pipe clamp still attached to the rear brake pipe from the swingarm. • Undo and remove the screw and re- move the speed sensor. •...
  • Page 176 RX SX 125 Chassis • Working from the left side, undo and remove the swingarm pin (7) and col- lect the two washers. • With the help of a second operator, re- move the swingarm from the chassis. SWINGARM REMOVAL •...
  • Page 177 RX SX 125 Chassis SWINGARM PIN With a dial gauge check if the pin eccentricity ex- ceeds the limit value. Otherwise, replace the pin. Maximum pin eccentricity: 0.3 mm (0.01 in) Installing CAUTION REPLACE BOTH ROLLER CASINGS • Clean all the swingarm coupling com- ponents completely and grease them with lithium grease.
  • Page 178 RX SX 125 Chassis • The correct adjustment of the swing- arm pin clearance is obtained by prop- erly seating the ring nut set bushing (6) and screwing it another 1 / 4 of a turn. • Firmly hold the bushing (6) and tighten the ring nut (7) using a special tool.

  • Page 179: Drive Chain

    RX SX 125 Chassis • Place the connecting rod assembly on the swingarm. • Insert the screw from the right side. • Fit the washer and tighten the nut (9). • Position the brake hoses on the swing- arm. •...
  • Page 180 RX SX 125 Chassis Removing • Loosen the chain tension. • Rotate the rear wheel until the master link can be identified. • Slide off the clip. • Remove the plate underneath. • Remove the master link from the op- posite side.
  • Page 181 RX SX 125 Chassis • Check the chain tensioner roller for wear. • Finally, check the swingarm protection pad for wear. Installing • Check the correct positioning of the chain on the pinion and the crown. • Fit the chain with the two ends joined at a point between the pinion and the crown on the lower branch of the chain.
  • Page 182 RX SX 125 Chassis • Move the vehicle forward so as to also check the chain vertical oscillation in other positions; clearance should remain constant during all wheel rotation phases. CAUTION IF CLEARANCE IS GREATER AT SOME POSITIONS, THIS MEANS THAT SOME CHAIN LINKS ARE FLATTENED OR JAMMED.
  • Page 183 RX SX 125 Chassis • Undo and remove the upper screw (2) and collect the nut (6). • Undo and remove the screw (3) and collect the rubber ring (5). • Remove the upper chain guide slider (4). • Undo and remove the two lower screws (2).
  • Page 184 RX SX 125 Chassis 2. Silencer 3. Silencer clamp 4. Muffler protection 5. Silent-block 6. M6 Flanged self-locking nut 7. Insulating washer 8. Clip M6 9. TE flanged screw M6x16 10.Traction cyl. helical spring 11.TCEI M6x16 screw 12.Silencer plate 13.M6x12 TE flanged screw 14.6.4X11X0.5 spring washer...
  • Page 185 RX SX 125 Chassis • Undo and remove both screws that fix the silencer support bracket to the chassis and collect the washer. • Slide off the silencer backwards. See also Side body panels Removing the exhaust manifold • Undo and remove the screw that fixes the muffler to the chassis and collect the washer.
  • Page 186 RX SX 125 Chassis • Undo and remove the two fixing nuts of the manifold and collect bracket and washer. • Slide off the muffler forwards. CAUTION WHEN REFITTING, REPLACE THE EXHAUST GASKET AND CHECK THE CORRECT POSITION- ING OF THE FIXING BRACKETS.
  • Page 187 RX SX 125 Chassis The solenoid controlled by the rave control unit opens the exhaust valve at 8000 rpm. TROUBLESHOOTING • Check that the 7.5 A fuse is in good conditions. • Check the if the solenoid is working properly by powering it directly with a 12 V battery.
  • Page 188 RX SX 125 Chassis • Check that the solenoid activates the RAVE at 0.5-sec pulse intervals. Removing • Remove the fuel tank • Remove the battery with the battery housing. PARTIAL • Detach the protection casing (1). • Undo and remove both screws (2) and collect the locking washers.
  • Page 189 RX SX 125 Chassis TOTAL • Undo and remove both RAVE valve screws and collect the locking wash- ers. • Take out the exhaust valve unit from the cylinder. • Disconnect the connector of the sys- tem control unit. •...
  • Page 190 RX SX 125 Chassis CYLINDER GASKET The cylinder gasket (4) must be replaced at every refitting operation. SOLENOID • Check the control unit as per the dia- gram. Installing • Remove the fuel tank. • Remove the battery with the battery housing.
  • Page 191 RX SX 125 Chassis • Connect the connector of the control unit to the system. • Connect the flexible cable (3) to the stem valve housing (4). • Rotate the stem valve housing (4) by 180°. CAUTION THE CABLE CONNECTION SHOULD BE FACING DOWN- WARDS..
  • Page 192 INDEX OF TOPICS COOL SYS OOLING SYSTEM...

  • Page 193: Circuit Diagram

    RX SX 125 Cooling system Circuit diagram 1. RH Radiator 2. Radiator cap 3. LH Radiator 4. T-shaped bushing 5. 11.5x23x9.3 rubber cap 6. Clip M6 7. Radiators water pipe 8. Radiator-pump pipe 9. D24.24.5x8.6 clic clamp 10.Head-radiator pipe 11.d.7x11 fuel pipe...

  • Page 194: Coolant Replacement

    RX SX 125 Cooling system 12.D11x6.6x1 green clic clamp 13.D28x8.6 clic clamp 14.D23.5x8 clic clamp 15.D23.5x8 clic clamp 16.D10.1 clamp 17.5x9 pipe 18.TE flanged screw M6x25 Coolant replacement CAUTION DO NOT USE YOUR VEHICLE IF THE COOLANT IS BELOW THE MINIMUM LEVEL.

  • Page 195: Water Pump

    RX SX 125 Cooling system • Top-up with coolant. CAUTION DO NOT DISPOSE OF THE FLUID INTO THE ENVIRONMENT. See also Side body panels Water pump • Remove the water pump control gear. • Undo and remove the M5 fixing screw.
  • Page 196 RX SX 125 Cooling system • Remove the water pump with the help of a square screwdriver. REFITTING • Upon refitting follow the removal steps but in reverse order, paying special attention to the alignment of the water pump control wheel, which must be aligned with the reference on the crankcase when refitting.
  • Page 197 RX SX 125 Cooling system • Working on both sides, release the clamps between the aluminium tube and the rubber hose in the radiator. • Remove the right and left delivery pipes. • Remove the radiator breather pipe. • Working on both sides, undo the two screws and collect the spacer.
  • Page 198 RX SX 125 Cooling system • Operating on both sides of the chassis, undo and remove the two screws and collect the washers and remove the ra- diator. CAUTION THE RADIATORS ARE INTERCONNECTED THROUGH THE LOWER PIPE. COOL SYS - 198...
  • Page 199 INDEX OF TOPICS BODYW ODYWORK...
  • Page 200 RX SX 125 Bodywork Seat • Place the vehicle on the service stand. • Insert the key in the lock. • Turn the key anticlockwise. • Lift and remove the saddle. UPON REFITTING: BEFORE LOWERING AND LOCKING THE SADDLE, CHECK THAT THE KEY HAS NOT BEEN LEFT INSIDE THE GLOVE-BOX / TOOLKIT COMPARTMENT.
  • Page 201 RX SX 125 Bodywork • Slide off the front brake pipes from the hose guide. • Remove the headlight assembly for- wards, releasing it carefully from the front fitting slots on the mudguard. • Remove the rubber cap and discon- nect the instrument panel connector.
  • Page 202 RX SX 125 Bodywork TURN INDICATORS • If necessary, remove the turn indica- tors working from any side, then undo and remove the screw and carefully slide off the gauge with cables. LICENSE PLATE LIGHT • If necessary, remove the license plate light, undo and take out the screw and carefully slide off the light with cables.
  • Page 203 RX SX 125 Bodywork • Unscrew and remove the screw and collect the collar. • Undo and remove the lower screw. • Remove the central side fairing. FRONT FAIRING • Remove saddle, central fairings and tank cover. • Undo and remove the right-side screw and collect the nut from the left side.
  • Page 204 RX SX 125 Bodywork • Undo and remove the fixing screw. The following operations refer to only one fair- ing, but are valid for both. • Undo and remove the radiator fixing screw. • Remove the front side fairing. CHASSIS COVER •...
  • Page 205 RX SX 125 Bodywork • Undo and remove the lower screw, paying attention to the rear brake lever placed on the right-hand side. Upon refitting, replace clamps with the same type and size of clamps. See also Seat Fuel tank Air box •...
  • Page 206 RX SX 125 Bodywork • Working from both sides, undo and re- move the screw and collect the wash- • Remove the clamp and slide off the piping. • Loosen the clamp and release the sleeve. • Undo and remove the two screws and move the control unit sideways.
  • Page 207 RX SX 125 Bodywork • Remove the clamp. • Release the fuses housing from the fil- ter casing sliding it upwards. • Release the relay from the filter casing sliding it rightwards. • Disconnect the connector. • Remove the chassis clamp.

  • Page 208: Fuel Tank

    RX SX 125 Bodywork • Operating from both sides, undo and remove the chassis fixing screw and collect the nut. CAUTION ONCE THE CHASSIS IS RELEASED PAY ATTENTION TO THE REAR SIDE OF THE MOTORCYCLE AND PLACE IT ON THE GROUND LOWERING THE HOIST.
  • Page 209 RX SX 125 Bodywork Seat • Remove the front side fairings and the tank cover. • Undo and remove the two screws pay- ing attention to the corresponding col- lars and spacers. • Lift the tank from the side and close the fuel supply valve.

  • Page 210: Front Mudguard

    RX SX 125 Bodywork Front mudguard • Undo and remove the two screws and collect the washers. • Undo and remove the two upper screws and collect the nuts (1) and washers. • Unscrew and remove the four screws (2) and collect the washers.
  • Page 211 RX SX 125 Bodywork • Lift the fuel tank without removing it. • Remove the clamp. • Disconnect the oil level probe connec- tors. • Place a container of suitable capacity underneath the vehicle. • Loosen the clamp and drain the reser- voir in the container.
  • Page 212 RX SX 125 Bodywork • Tighten the bleed screw again and fill the reservoir until the oil reaches the recommended level. Battery BATTERY REMOVAL • Remove the saddle. • Make sure the ignition switch is set to «OFF». • Disconnect the negative ( -) lead first and then the positive (red) (+) one.
  • Page 213 RX SX 125 Bodywork • To detach the rear fairings from the tail section, check the fittings alongside the rim, from the lower side of the tail. • Remove fairings and tail. BODYW - 213...
  • Page 214 INDEX OF TOPICS PRE DE DELIVERY...
  • Page 215 RX SX 125 Pre-delivery Carry out the listed checks before delivering the vehicle. WARNING BE EXTREMELY CAUTIOUS WHEN HANDLING FUEL. Aesthetic inspection - Paintwork - Fitting of Plastic Parts - Scratches - Dirt Tightening torques inspection - Safety locks: front and rear suspension unit...

  • Page 216: Road Test

    RX SX 125 Pre-delivery - Through the diagnosis tool, check that the last mapping version is present in the control unit/s and, if required, program the control unit/s again: consult the technical service website to know about available upgrades and details regarding the operation.
  • Page 217 RX SX 125 Pre-delivery - Response to throttle control - Stability when accelerating and braking - Front and rear brake efficiency - Front and rear suspension efficiency - Abnormal noise Static test Static check after test drive: - Restarting when warmed up...
  • Page 218 Air filter: 28 Battery: 57, 64, 212 Brake: Bulbs: Carburettor: 130 Chain: 179, 182 Clutch: 31, 101–104 Coolant: 194 Display: 137 Fork: 145, 146, 150, 153, 158 Fuel: 205, 208 Fuses: 63 Gearbox oil: 26 Headlight: 33, 200 Horn: 60 Identification: 10 Instrument panel: Maintenance: 8, 25...
  • Page 219 Tank: 205, 208, 210 Transmission: 12 Tyres: 14 Warning lights:...

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