Yamaha F30B 2018, Service Manual

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Camshaft and valve
4. Measure:
• Stem runout
Above specification

Replace.
Checking the valve guide
Before checking the valve guides, make sure
that the valve stem diameter is within specifica-
tion.
1. Measure:
• Inside diameter “a”
Above specification

Replace.
2. Calculate:
• Valve stem to valve guide clearance
Out of specification

Replace the valve
and valve guide.
Replacing the valve guide
After replacing a valve guide, check the valve
seat contact area.
1. Remove:
• Valve guide “1” (from the combustion
chamber side)
Runout limit EX
0.01 mm (0.0004 in)
Runout limit IN
0.01 mm (0.0004 in)
Inside diameter IN
5.500–5.512 mm (0.2165–
0.2170 in)
Inside diameter EX
5.500–5.512 mm (0.2165–
0.2170 in)
a
Valve stem to valve guide clear-
ance = valve guide inside diameter
– valve stem diameter
Clearance IN
0.010–0.037 mm (0.0004–
0.0015 in)
Limit
0.070 mm (0.0028 in)
Clearance EX
0.025–0.052 mm (0.0010–
0.0020 in)
Limit
0.070 mm (0.0028 in)
Valve guide remover/installer “2”
90890-06801
Valve guide remover “2”
YB-06801
1
2