Honda Metropolitan CHF50 Service Manual page 156

CYLINDER HEAD/VALVES
Reface the seat Use a 45° seat cutter, remove any roughness or
with a 45-degree irregularities from the seat.
cutter whenever a
valve guide is
replaced.
TOOLS:
Seat cutter, 20.5 mm (45° IN)
Seat cutter, 17 mm (45° EX)
Cutter holder, 4.5 mm
07780-0011000
07780-0011100
07781-0010600 or
equivalent
commercially
available in U.S.A.
Use a 32° flat cutter, remove 1/4 of the existing
valve seat material.
TOOLS:
Flat cutter, 22 mm (32° IN)
Flat cutter, 20 mm (32° EX)
Cutter holder, 4.5 mm
07780-0012601
07780-0013200
07781-0010600 or
equivalent
commercially
available in U.S.A.
Use a 60° interior cutter, remove 1/4 of the existing
valve seat material.
TOOLS:
Interior cutter, 20.5 mm (60° IN) 07780-0014300
Interior cutter, 17 mm (60° EX) 07780-0014600
Cutter holder, 4.5 mm 07781-0010600 or
equivalent
commercially
available in U.S.A.
Using a 45° seat cutter, cut the seat to the proper
width.
VALVE SEAT WIDTH: 1.0 mm (0.04 in)
Make sure all pitting and irregularities are removed.
ROUGHNESS
OIL SEAT WIDTH
OIL SEAT WIDTH
0 mm (0.039 in)
8-16