Yamaha F150A Service Manual page 117

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
prevent chatter marks.
3. Use a 30° cutter to adjust the contact
width of the top edge of the valve seat.
b
b Previous contact width
4. Use a 60° cutter to adjust the contact
width of the bottom edge of the valve
seat.
63P3F11
S63P5240
b Previous contact width
5. Use a 45° cutter to adjust the contact
b Previous contact width
c Specified contact width
6. If the valve seat contact area is too wide
30˚
S69J5880
b Previous contact width
b
width of the valve seat to specification.
b
c
45˚
and situated in the center of the valve
face, use a 30° cutter to cut the top edge
of the valve seat, a 60° cutter to cut the
bottom edge to center the area and set
its width.
Cylinder head
1
60˚
2
S69J5890
3
4
S69J5900
5
6
7
8
9
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