Yamaha YFM50S Service Manual page 105

CAMSHAFT, ROCKER ARMS AND VALVES
2. Check:
• rocker arm shaft
Blue discoloration/excessive wear/pitting/
scratches → Replace or check the lubrica-
tion system.
3. Check:
• camshaft lobe
Excessive wear → Replace the camshaft.
4. Measure:
• rocker arm inside diameter a
Out of specification → Replace.
Rocker arm inside diameter
10.000 ~ 10.015 mm
(0.3937 ~ 0.3943 in)
5. Measure:
• rocker arm shaft outside diameter a
Out of specification → Replace.
Rocker arm shaft outside diame-
ter
9.981 ~ 9.991 mm
(0.3930 ~ 0.3933 in)
6. Calculate:
• rocker-arm-to-rocker-arm-shaft clearance
NOTE:
_
Calculate the clearance by subtracting the
rocker arm shaft outside diameter from the
rocker arm inside diameter.
Above 0.08 mm (0.0031 in) → Replace the
defective part(s).
Rocker-arm-to-rocker-arm-shaft
clearance
0.009 ~ 0.034 mm
(0.0004 ~ 0.0013 in)
<Limit>: 0.08 mm (0.0031 in)
4 - 16
ENG