Yamaha FZR400 1988-1989, Service Manual

Page: 163 / 477

INSPECTION AND REPAIR
302 027
302 017
VALVE SEAT
1. Clean:
??
Valve face
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Valve seat
Remove carbon deposit.
2. Inspect:
??
Valve seat
Pitting/Wear Reface valve seat.
3. Measure:
??
Valve seat width
Out of specification Reface valve seat.
Valve Seat Width
Intake
0.9 1.1 m m (0.035 0.043 in)
Exhaust
0.9 1.1 m m (0.035 0.043 in)
Valve seat width measurement steps:
??
Apply the Mechanic’s bluing dye (Dykem)
to the valve face.
??
install the valve into the cylinder head.
??
Press the valve through the valve guide and
onto the valve seat to make a clean pattern.
??
Measure the valve seat width. Whether the
valve seat and valve face made contact,
bluing will have been removed.
e l f t h e v a l v e s e a t w i d t h i s t o o w i d e , t o o
narrow, or seat has not centered. The valve
seat must be refaced.
4. Reface:
??
Valve seat
Use 45” and 60” Valve Seat Cutter.
Valve Seat Cutter Set :
P/N YM-91043