Yamaha YFZ450S 2003 Service Manual page 171

VALVES AND VALVE SPRINGS
2. Replace:
M
NOTE:
_
To ease guide removal, installation and to
maintain correct fit, heat the cylinder head to
100 °C (212 °F) in an oven.
a. Remove the valve guide using a valve guide
b. Install the new valve guide using a valve
c. After installing the valve guide, bore the
NOTE:
_
After replacing the valve guide reface the valve
seat.
L
3. Check:
4 - 28
• valve guide
MMM M MMM M M MMM M M MMM
remover 1.
guide remover 1 and valve guide installer
2.
valve guide using a valve guide reamer 3
to obtain proper stem-to-guide clearance.
Valve guide remover
Intake (ø 4.5)
P/N. YM-04116/90890-04116
Exhaust (ø 5)
P/N. YM-04097/90890-04097
Valve guide installer
Intake (ø 4.5)
P/N. YM-04117/90890-04117
Exhaust (ø 5)
P/N. YM-04098/90890-04098
Valve guide reamer
Intake (ø 4.5)
P/N. YM-04118/90890-04118
Exhaust (ø 5)
P/N. YM-04099/90890-04099
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• valve face
Pitting/wear → Grind the face.
• valve stem end
Mushroom shape or diameter larger than
the body of the stem → Replace.
ENG
M M MMM M M MMM M
L L LLL L L LLL L
MMM
LLL