Checking The Valve Springs - Yamaha TW125 1999 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) b
h. Install the valve into the cylinder head.
i. Press the valve through the valve guide and
j. Measure the valve seat width c again. If the
EAS00241

CHECKING THE VALVE SPRINGS

The following procedure applies to all of the
valve springs.
1. Measure:
2. Measure:
b Installed length
3. Measure:
4-22
face and repeat the above steps.
clean off all of the lapping compound from
the valve face and valve seat.
onto the valve face.
onto the valve seat to make a clear impres-
sion.
valve seat width is out of specification, reface
and lap the valve seat.
S valve spring free length a
Out of specification ! Replace the valve
spring.
Valve spring free length (intake
and exhaust)
Inner spring
35.5 mm Limit: 33.5 mm
Outer spring
37.2 mm Limit: 35.2 mm
S compressed spring force a
Out of specification ! Replace the valve
spring.
Compressed spring force
Intake and exhaust inner
spring
8.4 X 10.2 kg at 30.5 mm
Intake and exhaust outer
spring
16.6 X 20.4 kg at 32.0 mm
S valve spring tilt a
Out of specification ! Replace the valve
spring.
Spring tilt limit
Intake and exhaust inner spring
2.5_/1.5 mm
Intake and exhaust outer spring
2.5_/1.6 mm
ENG