Yamaha XVS6501997, Service Manual

Page: 127 / 327

4-23
VALVES AND VALVE SPRINGS
ENG
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NOTE:
NOTE:
2. Replace:
S
Valve guide
Replacement steps:
To ease guide removal, installation and to main-
tain correct fit heat the cylinder head in an oven
to 100
_
C.
D
Remove the valve guide using a valve guide
remover
1 .
D
Install the new valve guide using a valve
guide remover
1 and valve guide installer
2 .
D
After installing the valve guide, bore the valve
guide using a valve guide reamer
3 to obtain
proper stem-to-guide clearance.
Valve guide remover & installer
(7.0 mm):
90890-04018
After replacing the valve guide reface the valve
seat.
3. Inspect:
S
Valve face
Pitting/ wear
Grind the face.
S
Valve stem end
Mushroom shape or diameter larger than
the body of the stem
Replace.
4. Measure:
S
Margin thickness
a
Out of specification Replace.
Margin thickness:
Intake:
1.0 1.4 mm
<Limit>: 0.8 mm
Exhaust:
1.0 1.4 mm
<Limit>: 0.8 mm