Yamaha RAPTOR YFM125RA Service Manual page 74

• 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:
• Spark plug cap
• Spark plug
• Intake tappet cover "1"
• Exhaust tappet cover "2"
• Camshaft sprocket cover "3"
2. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw "2"
3. Measure:
• Valve clearance
Out of specification → Adjust.
Valve clearance (cold)
Intake
0.08–0.12 mm (0.0032–0.0047
in)
Exhaust
0.10–0.14 mm (0.0039–0.0055
in)
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a. Turn the crankshaft counterclockwise.
b. When the piston is at TDC on the compres-
sion stroke, align the mark "a" on the gen-
erator rotor with the stationary pointer "b"
on the generator rotor cover.
PERIODIC MAINTENANCE
c. Align the mark "c" on the camshaft sprocket
with the stationary pointer "d" on the cylin-
der head.
d. Measure the valve clearance with a thick-
ness gauge "1".
Out of specification → Adjust.
Thickness gauge
90890-03180
Feeler gauge set
YU-26900-9
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4. Adjust:
• Valve clearance
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a. Loosen the locknut "1".
b. Insert a thickness gauge "2" between the
end of the adjusting screw and the valve
tip.
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