Yamaha TW200 Service Manual page 104

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IN_S_P_E_C_T_IO_N_A_N_D_R_E_P_A_IR_I~GI~I
[CJ
Valve seat is too narrow and right up near valve
margin.
Valve seat cutter set
Desired result
30° cutter, first
To center the seat
Use
and to achieve its
width of 1.0 mm
45° cutter
(0.039
in)
[QI
Valve seat is too narrow and is located down
near the bottom edge of the valve face.
Valve seat cutter set Desired result
60° cutter,
To center the seat
Use
first
and increase
45° cutter
its width
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5. Lap:
-Valve face
-Valve seat
NOTE: _
When refacing the valve seat or replacing the
valve and valve guide, the valve seat and valve
face should be lapped.
Lapping steps:
- Apply a coarse lapping compound to the valve
face.
1111.1 ---
Be sure no compound enters the gap be-
tween the valve stem and guide.
- Apply a molybdenum disulfide oil to the valve
stem.
-Install the valve into the cylinder head.
302-024
4-24