Yamaha YFM400FWA 2000 5GH3-AE1, Service Manual

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ENG
CAMSHAFT, ROCKER ARMS AND VALVES
2.Replace:
●
Valve guide
*********************************
Replacement steps:
NOTE:
To ease guide removal, installation and to
maintain correct fit, heat the cylinder head
to 100 ˚C (212 ˚F) in an oven.
●
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.
NOTE:
After replacing the valve guide reface the
valve seat.
*********************************
Valve guide remover (7 mm):
P/N. YM-01225-A, 90890-01225
Valve guide installer:
P/N. YM-04017, 90890-04017
Valve guide reamer (7 mm):
P/N. YM-01227, 90890-01227
3.Inspect:
●
Valve face
Pitting/wear
→
Grind the face.
●
Valve stem end
Mushroom shape or diameter larger than
the body of the stem
→
Replace.
4.Measure:
●
Margin thickness
a
Out of specification
→
Replace.
Margin thickness:
Intake:
1.0 ~ 1.4 mm (0.0394 ~ 0.0551 in)
Exhaust:
0.8 ~ 1.2 mm (0.0315 ~ 0.0472 in)