Service manual

5-70
E
POWR
VALVES AND VALVE SPRINGS
Valve seat reface
1. Reface the valve seat with the valve seat
cutter.
2. Cut the surface of the valve seat with a 45°
cutter by turning the cutter clockwise until
the valve seat face has become smooth.
a Slag or rough surface
CAUTION:
Do not over cut the valve seat. Be sure to
turn the cutter evenly downward at a pres-
sure of 40–50 N (4–5 kgf, 8.8–11 lbf) to pre-
vent chatter marks.
Valve seat cutter holder:
Intake (4.0 mm):
90890-06811
Exhaust (4.5 mm):
90890-06812
Valve seat cutter:
30° (intake):
90890-06815
45° (intake):
90890-06814
60° (intake):
90890-06813
30° (exhaust):
90890-06328
45° (exhaust):
90890-06312
60° (exhaust):
90890-06315
Valve seat cutter set:
YM-91043-C
3. Use a 30° cutter to adjust the contact width
of the top edge of the valve seat.
b Previous contact width
30˚
b