Refacing The Valve Seat - Yamaha F6AMH Service Manual

CAMSHAFT AND VALVES
(4)Bore the valve guide using the valve
guide reamer.
Valve guide reamer:
NA/90890-06804
NOTE:
When installing and removing the valve
guide reamer, apply machining oil and turn
the reamer clockwise

REFACING THE VALVE SEAT

NOTE:
After refacing the valve seat or replacing
the valve and valve guide, lap the valve
seat and valve face.
Reface:
Valve seat


CAUTION:
When turning the valve seat cutter, keep
an even downward pressure (4 - 5 kg) to
prevent chatter mark.
Valve seat width
(intake valve and exhaust valve):
0.6 - 0.8 mm (0.02 - 0.03 in)
Valve seat cutter set:
YM-91043-C/90890-06803
Valve seat lapper:
NA/90890-04101
Cut section of follows
Section
A
B
C
5-49
Cutter
90°
45°
30°