Valve Seat Refacing - Honda 2010 CRF250R Service Manual

CYLINDER HEADNALVES
The valves cannol
be ground.
If
a
valve face ;s burned
or badly worn
or
if it
contacts
lhe
seat
unevenly. replace
the valve.
Follow the refacing
manufacturer's
operating
ins/ructions.
Contact area (too high or 100 low)
- Reface the valve seal.
VALVE SEAT REFACING
Valve seat culters/grinders or equivalent valve seal
refacing equipment are recommended to correct worn
valve
seats.
If the contact area is too high on the valve, the seal
must be lowered using a 32° flat culler.
If the contact area is too low on the valve, the seal must
be raised using a
60·
interior cutler.
Reface the
seal Use a 45" seal culter,
remove
any roughness or
with a 45'
curter
irregularities from the seal.
whenever
a
valve
gUIde
IS
replaced.
TOOLS:
8-24
IN :
Seal cutter, 33 mm
Cutter holder, 5.0 mm
EX:
Seat cutter, 24.5 mm
Cutter holder, 4.5 mm
07780'()010800
07781-0010400
07780-0010100
07781-0010600
or equivalent commercially available in U.S.A.
TOO LOW TOO HIGH
45·
60·
" OLD SEAT
" "'" WIDTH
32·
I ~=~"~
..
CONTACT TOO LOW - - - - - '
OLD SEAT
~IOTH
~
..
-------'. 60·
~
ROUGHNESS