Honda 1988 Z50R Service Manual page 58

CYLINDER HEAD/VAlVES
Use the 32 degree cutler to remove 1/4 of the eJCisting valve seal
material.
Use the 60 degree cutter to remove the lower 1/4 of the old seat .
Remove the cutter and inspect the area you have just cut.
Install the 45 degree finish cutter and cut the seat to the proper
width.
STANDARD SEAT WIDTH : 1.2
mm
10.047
in)
NOTE
Make sure that all pitting and irregularities are removed. Refinish
if necessary.
Apply a thin coating of Prussian Blue to the valve seat.
Without reating the valve, insert it through the valve guide and
onto the seat to make a clear pattern.
If
the contact surface is too
high,
cut
the seat using the 32 degree
cutter, then cut the seat to the proper width with the 45 degree
finish cutter.
If the contact surface is too low, cut the seat using the 60 degree
cutter, then cut the seat to the proper width with 45 degree fin -
ish cutter.
NOTE
The location of the valve seat in relation to the valve face is very
important for good sealing.
6-12
--
OLD SEAT WIDTH
32°
OLD SEAT WI DTH
.2 mm
(0 .047
in)
CONTACT TOO HIGH
~o~o
SEAT WIDTH
~
\
CONTACT TOO LOW
~ ~D
SEAT WIDTH
~