Yamaha F75F - Checking the Valve Guide; Replacing the Valve Guide

Camshaft and valve
7-33
3. Measure:
• Stem d
iameter “a”
Below specification  Replace.
4. Measure:
• Stem runout
Above specification  Re
place.
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.
Diameter IN
5.475–5.490 mm (0.2156–0.2161
in)
Limit
5.445 mm (0.2144 in)
Diameter EX
5.460–5.475 mm (0.2150–0.2156
in)
Limit
5.430 mm (0.2138 in)
Runout limit IN
0.01 mm (0.0004 in)
Runout limit EX
0.01 mm (0.0004 in)
a
Inside diameter IN
5.504–5.522 mm (0.2167–0.2174
in)
Inside diameter EX
5.504–5.522 mm (0.2167–0.2174
in)
Valve stem to valve guide clearance
= Valve guide
inside diameter – Valve
stem diameter
Clearance IN
0.014–0.047 mm (0.0006–0.0019
in)
Limit
0.070 mm (0.0028 in)
Clearance EX
0.029–0.062 mm (0.0011–0.0024
in)
Limit
0.080 mm (0.0032 in)
a