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ENG
VALVES AND VALVE SPRINGS
6. Measure:
• stem runout
Out of specification
-->
Replace the valve.
•
When installing a new valve, always replace
the valve guide.
•
If the valve is removed or replaced, replace
the valve stem oil seal.
NOTE:
Runout limit
0.030 mm (0.0012 in)
CHECKING THE VALVE SEAT
The following procedure applies to all of the valves
and valve seats.
1. Eliminate:
• carbon deposits
2. Check:
• valve seat
Pitting/Wear
-->
Replace the cylinder head.
3. Measure:
• valve seat width
a
Out of specification
-->
Replace the cylinder
head.
Valve seat width
Intake
0.90 ~ 1.10mm (0.03 ~ 0.04 in)
Exhaust
0.90 ~ 1.10mm (0.03 ~ 0.04 in)
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a. Apply Mechanic’s blueing dye (Dykem)
b
onto
the valve face.
b. Install the valve into the cylinder head.
c. Press the valve through the valve guide and
onto the valve seat to make a clear impression.
d. Measure the valve seat width.
T TT
T TT
T TT
T TT
T TT
T TT
T TT
T TT
T TT
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T
T
T TT
T TT
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a
b
Where the valve seat and valve face contacted
one another, the blueing will have been removed.
NOTE:
5-26
Summary of Contents for YBR250 2007
Page 1: ...YBR250 SERVICE MANUAL 5D1 F8197 E0 2007 ...
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