Honda SH300 2006 Manual page 232

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