Yamaha Mio - Page 63

3 - 9
CHK
ADJ
ADJUSTING THE VALVE CLEARANCE
4. Measure:
• valve clearance
Out of specification → Adjust.
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a. Turn the crankshaft clockwise.
b. When the piston is at the Top Dead Center
(TDC) on the compression stroke, align the
“I” mark a in the camshaft sprocket with the
stationary b on the cylinder head.
c. Align the “I” mark c on the A.C. magneto
rotor with the stationary pointer d on the
crankcase.
d. Measure the valve clearance with a thick-
ness gauge 1.
Out of specification → Adjust.
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Valve clearance (cold)
Intake valve
0.06 ~ 0.10 mm
(0.0024 ~ 0.0039 in)
Exhaust valve
0.08 ~ 0.12 mm
(0.0031 ~ 0.0047 in)
b
a
d
c
1
5. 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.
c. Turn the adjusting screw 3 in direction a
or b until the specified valve clearance is
obtained.
Direction a
Valve clearance is
increased.
Direction b
Valve clearance is
decreased.
Tappet adjusting tool
90890-01311
2
1
3
a
b