Honda CBR125R Owner's Manual page 209

Use a 45° cutter, remove any roughness or irregu-
Reface the valve
°
larities from the seat.
seat with a 45
cutter when a valve
TOOLS:
guide is replaced.
Seat cutter, 24 mm (45° EX)
Seat cutter, 29 mm (45° IN)
Cutter holder, 5.0 mm
Using 32° cutter, remove the top 1/4 of the existing
valve seat material.
TOOLS:
Flat cutter, 27 mm (32° EX)
Flat cutter, 30 mm (32° IN)
Cutter holder, 5.0 mm
Using 60° cutter, remove the bottom 1/4 of the old
seat.
Remove the cutter and inspect the area you have
just removed.
TOOLS:
Interior cutter, 26 mm (60° EX)
Interior cutter, 30 mm (60° IN)
Cutter holder, 5.0 mm
Using a 45° cutter, cut the seat to proper width.
Make sure that all pitting and irregularities are
removed.
Refinish if necessary.
STANDARD SEAT WIDTH:
0.90 – 1.10 mm (0.035 – 0.043 in)
07780-0010600
07780-0010300
07781-0010400
VALVE SEAT CUTTER
07780-0013300
07780-0012200
07781-0010400
07780-0014500
07780-0014000
07781-0010400
CYLINDER HEAD/VALVES
ROUGHNESS
OLD SEAT WIDTH
32°
OLD SEAT WIDTH
60°
SEAT WIDTH
45°
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