Engine; Adjusting The Valve Clearance - Yamaha YFM70RY Service Manual

EAS20472

ENGINE

EAS20520

ADJUSTING THE VALVE CLEARANCE

The following procedure applies to all of the
valves.
TIP
• Valve clearance adjustment should be made
on a cold engine, at room temperature.
• When the valve clearance is to be measured or
adjusted, the piston must be at top dead center
(TDC) on the compression stroke.
1. Remove:
• Seat
• Front fender
• Fuel tank
Refer to "GENERAL CHASSIS" on page 4-1.
2. Remove:
• Intake tappet cover
• Exhaust tappet cover "1"
• Camshaft sprocket cover "2"
1
3. Disconnect:
• Spark plug cap "1"
4. Remove:
• Spark plug "2"
2
5. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw "2"
2
1
6. Measure:
• Valve clearance
Out of specification → Adjust.
Valve clearance (cold)
Intake
0.09–0.13 mm (0.0035–0.0051 in)
Exhaust
0.16–0.20 mm (0.0063–0.0079 in)
M MMM M MMM M M MMM M
a. Turn the crankshaft counterclockwise.
b. When the piston is at TDC on the compres-
sion stroke, align the punch mark "a" in the
camshaft sprocket with the stationary pointer
"b" on the cylinder head.
b
a
c. Align the TDC mark "c" on the AC magneto
rotor with the stationary pointer "d" on the AC
magneto cover.
d. Measure the valve clearance with a thickness
gauge "1".
Out of specification → Adjust.
3-4
ENGINE
2
M MMM M M MMM M M MMM M
d
1
MMM
c