Rocker Arm And Rocker Arm Shaft - Yamaha YFM250XL(C) Service Manual

4
INSPECTION AND REPAIR
2.Inspect:
Cam lobes
Pitting/Scratches/Blue discoloration →
Replace.
3.Measure:
Cam lobes
Use a Micrometer.
Out of specification → Replace.
Intake
Exhaust

ROCKER ARM AND ROCKER ARM SHAFT

1.Inspect:
Rocker arm shafts
Rocker arms
Wear/Damage → Replace.
*********************************
Rocker arm shaft and arm inspection steps:
Inspect the two areas on the rocker arm
for signs of unusual wear.
1) Rocker arm shaft hole.
2) Cam-lobe-contact surface.
Excessive wear → Replace.
Inspect the surface condition of the rocker
arm shaft.
Pitting/Scratches/blue discoloration →
Replace/Check lubrication.
Measure the inside diameter a of the
rocker arm hole.
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
rocker arm shaft.
Out of specification → Replace.
Rocker arm shaft outside diameter:
11.985 ~ 11.991 mm
(0.4718 ~ 0.4721 in)
4 - 28
ENG
Cam lobe Cam lobe
Limit "A" Limit "B"
36.437 mm 30.031 mm
(1.435 in) (1.182 in)
36.482 mm 30.152 mm
(1.436 in) (1.187 in)