Checking The Rocker Arm And Rocker Arm Shaft - Yamaha F30B 2018 Service Manual

f. After refacing the valve seat to the speci-
fied contact width, apply a thin, even layer
of lapping compound onto the valve seat,
and then lap the valve using the special
service tool "1".
Do not get the lapping compound on the
valve stem and valve guide.
1
Valve lapper "1"
90890-04101
Valve lapping tool "1"
YM-A8998
g. Recheck the valve seat contact area of the
valve. See "Checking the valve seat" (7-
36).
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Checking the rocker arm and rocker
arm shaft
1. Check:
• Rocker arms, rocker arm shaft, and con-
tact surface "a" of each rocker arm
Worn  Replace.
2. Measure:
• Rocker arm inside diameter "b" and rocker
arm shaft outside diameter "c"
Out of specification  Replace.
a
Rocker arm
Inside diameter IN
16.000–16.018
0.6306 in)
Inside diameter EX
16.000–16.018
0.6306 in)
Rocker arm shaft
Outside diameter IN
15.971–15.991
0.6296 in)
Outside diameter EX
15.971–15.991
0.6296 in)
7-39
Camshaft and valve
b
c
mm (0.6299–
mm (0.6299–
mm (0.6288–
mm (0.6288–