Valve Installation - Yamaha YFM250XL(C) Service Manual

4
INSPECTION AND REPAIR
2.Measure:
Valve spring installed force
Out of specification → Replace inner and
outer springs as a set.
a Installed length
Valve spring installed force
Inner spring
(IN/EX)
Outer spring
(IN/EX)

VALVE INSTALLATION

1.Lubricate:
Valve stem 1
Oil seal 2
Molybdenum disulfide oil:
2.
Install:
Intake valves
Exhaust valves
NOTE:
Be sure to reinstall in its original place.
3.Install:
Valve spring seat 1 (lower)
Oil seal 2
Valve 3
Valve spring 4 (inner)
Valve spring 5 (outer)
Valve spring seat 6 (upper)
Valve cotters 7
Use the Valve Spring Compressor.
Valve spring compressor:
P/N. YM-04019, 90890-04019
4 - 26
ENG
8.4 ~ 10.2 kg (18.5 ~ 22.5 lb)
at 30.5 mm (1.2 in)
16.6 ~ 20.4 kg (36.6 ~ 45.0 lb)
at 32.0 mm (1.26 in)