Checking The Valves And Valve Springs - Yamaha 2004 YXR660 Service Manual

VALVES AND VALVE SPRINGS
CHECKING THE VALVES AND VALVE
SPRINGS
1. Measure:
• stem-to-guide clearance
Stem-to-guide clearance =
valve guide inside diameter a –
valve stem diameter b
Out of specification → Replace the valve
guide.
2. Replace:
• valve guide
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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
remover 1.
b. Install the new valve guide using a valve
guide remover 1 and valve guide installer
2.
c. After installing the valve guide, bore the
valve guide using a valve guide reamer 3
to obtain proper stem-to-guide clearance.
NOTE:
After replacing the valve guide reface the valve
seat.
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4 - 27
ENG
Stem-to-guide clearance
Intake
0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
<Limit>: 0.08 mm (0.0031 in)
Exhaust
0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)
<Limit>: 0.10 mm (0.0039 in)
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Valve guide remover (ø 6)
P/N. YM-04064-A, 90890-04064
Valve guide installer (ø 6)
P/N. YM-04065-A, 90890-04065
Valve guide reamer (ø 6)
P/N. YM-04066, 90890-04066
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