Refacing The Valve Seat - Yamaha F15B Service Manual

Refacing the valve seat

1. Reface the valve seat with the valve seat
cutter.
45
5
Valve seat cutter holder:
90890-06316
Valve seat cutter:
5° (intake): 90890-06314
5° (exhaust): 90890-06313
45° (intake and exhaust):
90890-06312
60° (intake and exhaust):
90890-06315
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
6D45F11
60
6D450670
6D450690
6D450680
cC
Do not over cut the valve seat. Make sure
to turn the cutter evenly downward at a
pressure of 40–50 N (4–5 kgf, 8.8–11 lbf) to
prevent chatter marks.
3. Use a 5° cutter to adjust the contact width
of the top edge of the valve seat.
5
b Previous contact width
4. Use a 60° cutter to adjust the contact
width of the bottom edge of the valve
seat.
b Previous contact width
5. Use a 45° cutter to adjust the contact
width of the valve seat to specification.
45
b Previous contact width
c Specified contact width
Cylinder head
1
2
b
3
6D450700
4
5
6
60
7
6D450710
8
9
6D450720
5-28