Rocker Arm - Yamaha YFM450FAR Service Manual

CAMSHAFT, ROCKER ARMS AND VALVES
Not For Resale
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2.Check:
Rocker arms
G
Rocker arm shafts
G
Damage/wear → Replace.
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Checking steps:
G
Check the two contact areas on the rocker
arms for signs of abnormal wear.
1) Rocker arm shaft hole
2) Camshaft lobe contact surface
Excessive wear → Replace.
G
Check the surface of the rocker arm shafts.
Blue discoloration/pitting/scratches →
Replace/check lubrication.
Measure the inside diameter a of the rocker
G
arm holes.
Out of specification → Replace.
Rocker arm inside diameter:
12.000 ~ 12.018 mm
(0.4724 ~ 0.4731 in)
Measure the outside diameter b of the
G
rocker arm shafts.
Out of specification → Replace.
Rocker arm outside diameter:
11.981 ~ 11.991 mm
(0.4717 ~ 0.4721 in)
G
Calculate the clearance by subtracting the
rocker arm shaft outside diameter from the
rocker arm inside diameter.
Clearance greater than 0.08 mm (0.003 in)
→ Replace the defective part(s).
Rocker arm to shaft standard
clearance:
0.009 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
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ENG