Yamaha YZ426F/LC Fahrer- Und Wartungs-Handbuch Seite 292

VALVES AND VALVE SPRINGS
INSPECTION
Valve
1. Measure:
2. Replace:
Replacement steps:
NOTE:
To ease guide removal, installation and to
maintain correct fit heat the cylinder head in
an over to 100 ˚C (212 ˚F).
4 - 29
Stem-to-guide clearance
Stem-to-guide clearance =
valve guide inside diameter a –
valve stem diameter b
Out of specification → Replace the
valve guide.
Clearance (stem to guide):
Intake:
0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)
<Limit>: 0.08 mm (0.003 in)
Exhaust:
0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)
<Limit>: 0.10 mm (0.004 in)
Valve guide
Remove the valve guide using a valve
guide remover 1.
Install the new valve guide using a valve
guide remover 1 and valve guide installer
2.
After installing the valve guide, bore the valve
guide using a valve guide reamer 3 to obtain
proper stem-to-guide clearance.
Valve guide remover:
Intake 4.5 mm (0.18 in)
YM-4116/90890-04116
Exhaust 5.0 mm (0.20 in)
YM-4097/90890-04097
Valve guide installer:
Intake
YM-4117/90890-04117
Exhaust
YM-4098/90890-04098
Valve guide reamer:
Intake 4.5 mm (0.18 in)
YM-4118/90890-04118
Exhaust 5.0 mm (0.20 in)
YM-4099/90890-04099
ENG