Honda TRX680FA Service Manual page 216

CYLINDER HEAD/VALVE/CAMSHAFT
• Contact area (too high or too low)
- Reface the valve seat.
TOO LOW TOO HIGH
REFACING
NOTE:
• Follow the refacer manufacturer's operating
instructions.
• Be careful not to grind the seat more than neces-
say.
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.
Using a 45° seat cutter, remove any roughness or
irregularities from the seat.
TOOLS:
Seat cutter, 35 mm (IN/EX) 07780-0010400
Cutter holder, 5.5 mm 07781-0010101
or equivalent commercially available in U.S.A.
45°
32°
60°
CONTACT tOO HIGH
CONTACT TOO LOW
OLD SEAT WIDTH
ROUGHNESS
9-14