Checking The Valve Springs - Yamaha XP500 Service Manual

VALVES AND VALVE SPRINGS
e. Apply a fine lapping compound to the valve
f. After every lapping procedure, be sure to
g. Apply Mechanic's blueing dye (Dykem) onto
h. Install the valve into the cylinder head.
i. Press the valve through the valve guide and
j. Measure the valve seat width b again. If
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EAS00241

CHECKING THE VALVE SPRINGS

The following procedure applies to all of the
valve springs.
1. Measure:
2. Measure:
b Installed length
5 - 26
face and repeat the above steps.
clean off all of the lapping compound from
the valve face and valve seat.
the valve face.
onto the valve seat to make a clear impres-
sion.
the valve seat width is out of specification,
reface and lap the valve seat.
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• valve spring free length a
Out of specification → Replace the valve
spring.
Valve spring free length (intake
and exhaust)
35.59 mm (1.40 in)
<Limit>: 33.81 mm (1.33 in)
• compressed spring force a
Out of specification → Replace the valve
spring.
Compressed spring force
Intake valve spring
91.2 ~ 104.9 N at 30.4 mm
(9.3 ~ 10.7 kg at 30.4 mm,
20.5 ~ 23.6 lb at 1.20 in)
Exhaust valve spring
91.2 ~ 104.9 N at 30.4 mm
(9.3 ~ 10.7 kg at 30.4 mm,
20.5 ~ 23.6 lb at 1.20 in)
ENG
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