Yamaha F6AMH Service Manual page 280

A
B
C
D
CAMSHAFT AND VALVES
Refacing steps:
A
Valve seat is centered on valve face but
it is too wide.
Valve cutter seat
90° cutter
Use
lightly
30° cutter
B
Valve seat is in the middle of the valve
face but it is too narrow.
Valve cutter seat
Use 45° cutter
C
Valve seat is too narrow and it is near
the valve margin.
Valve cutter seat
90° cutter
Use
45° cutter
D
Valve seat is too narrow and it is near
the valve stem.
Valve cutter seat
30° cutter
Use
45° cutter
5-50
Desired result
To reduce the valve
seat width
Desired result
To increase the valve
seat width
Desired result
To center the valve
seat and set it width
Desired result
To center the valve
seat and set it width