Valve Seat Inspection/Refacing - Honda rebel 250 Service Manual

CYLINDER HEAD/VALVES
Install
a
new
O-ring
on
The
new
valve guide
Drive
in
the
guide
from
the top of the head.
TOOL:
Valve guide
driver,
5.6
mm
07742 -
0010100
Inspect the valve
guide for
damage.
Ream
the new
valve
guide
after installation.
Insert
the
reamer from
the
combustion
chamber
side of the
head and
also always rotate the
reamer
clockwise.
TOOL:
Valve guide reamer,
5.485
mm
07984 -
0980000
or
07984
-
098000D
(US.
A.
only
I
NOTE
•
Use
cutting
oil
on
the
reamer
during
this operation.
Clean the
cylinder
head thoroughly
to
remove any
metal
particles.
Ref8ce the valve seat (see below).
VALVE SEAT INSPECTION/REFACING
Clean
the intake and exhaust
valves thoroughly
to
remove
carbon
deposits.
Apply
a light
coating of Prussian Blue to the valve
seats.
Lap the valves
and
seats using
a
rubber hose
or
other hand-
lapping
tool.
Remove
and
inspect the
valves.
CAUTION
• The wives cannot be ground.
If
a valve face
is
burned nr badly
worn or
if
it
contacts the seat unevenly, replace the valve
Inspect the width
of
each valve
seat.
STANDARD
1.0-
1.1
mm
(0.039
-
0.043
In)
SERVICE
LIMIT:
1.8
mm
(0.07 In)
If
the seat
is
too wide, too narrow
or
has
low
spots, the seat
must
be
ground.
7-11