Honda SH300I 2006, Manual

Page: 232 / 511

CYLINDER HEAD/VALVES
9-16
• Contact area (too high or too low)
– Reface the valve seat.
REFACING
Follow the refacing
manufacturer's
operating instruc-
tions.
Valve seat cutters/grinders or equivalent valve seat
refacing equipment are recommended to correct
worn valve seats.
If the contact area is too high on the valve, the seat
must be lowered using a 32
°
flat cutter.
If the contact area is too low on the valve, the seat
must be raised using a 60
°
interior cutter.
Reface the seat
with a 45
°
cutter
whenever a valve
guide is replaced.
Use a 45
°
seat cutter to remove any roughness or
irregularities from the seat.
TOO LOW TOO HIGH
32
°
45
°
60
°
OLD SEAT
WIDTH
OLD SEAT
WIDTH
60
°
32
°
CONTACT TOO LOW
CONTACT TOO HIGH
TOOLS:
Seat cutter, 27.5 mm (45
°
IN) 07780-0010200
Seat cutter, 24 mm (45
°
EX) 07780-0010600
Cutter holder, 4.5 mm 07781-0010600
or equivalent commercially available
ROUGHNESS