Valve Seat Inspection - Yamaha EF1000iS Service Manual

CYLINDER (CRANKCASE 1) AND VALVE
a
a
c

VALVE SEAT INSPECTION

1. Remove carbon deposits from the valve
face and valve seat.
2. Apply a small amount of coarse mechan-
ic's blueing dye (Dykem) to the valve
face.
3. Insert the vale into the valve guide and
use a valve lapper to contact the valve
face with the valve seat.
NOTE:
Do not rotate the valve while the valve face is
contacting the valve seat.
4. Measure:
9 Valve face contact width a
5. Measure:
9 Valve seat contact width b
b
3-33
ENG
Make sure that the contact width along
the entire valve face is within specifica-
tions.
Out of specification/rough/
eccentric/wear → Replace.
Valve face contact width:
(Intake/Exhaust)
0.8 mm (0.03 in)
Limit:
1.8 mm (0.07 in)
Make sure that the contact width along
the entire valve seat is within specifica-
tions.
Out of specification/rough/
eccentric/wear → Replace.
Valve seat contact width:
(Intake/Exhaust)
0.5 mm (0.02 in)