Valve Seat Inspection/Refacing - Honda Metropolitan CHF50 Service Manual

CYLINDER HEAD/VALVES
Remove the new valve guides from the freezer.
Drive the new guides into the cylinder head from
the camshaft side while the cylinder head is still
heated.
TOOL:
Valve guide driver 07HMD-ML00101
Take care not to tilt
or lean the reamer
in the guide while
reaming.
Use cutting oil on
the reamer during
this operation.
VALVE GUIDE PROJECTION:
IN/EX: 9.05 - 9.35 mm (0.356 - 0.368 in)
Let the cylinder head cool to room temperature.
Ream the new valve guides after installation.
Insert the reamer from the combustion chamber
side of the head and also always rotate the reamer
clockwise.
TOOL:
Valve guide reamer, 4.5 mm
07HMH-ML00101 or
07HMH-ML0010B or
07HMH-ML0010A
(U.S.A. only)
Clean the cylinder head thoroughly to remove any
metal particles after reaming and reface the valve
seat as described below.
VALVE SEAT INSPECTION/REFACING
Clean the intake and exhaust valves thoroughly to
remove carbon deposits.
Apply a light coat of Prussian Blue to the valve
seats.
Tap the valve against the valve seat several times
using a hand-lapping tool, without rotating the
valve, to make a clear pattern.
The valves cannot
be ground. If the
valve face is burned
or badly worn or if it
contacts the seat
unevenly, replace
the valve.
Remove the valve and inspect the valve seat face.
The valve seat contact should be within the speci-
fied width and even all around the circumference.
STANDARD: 1.0 mm (0.04 in)
SERVICE LIMIT: 1.5 mm (0.06 in)
If the valve seat width is not within specification,
reface the valve seat (page 8-15).
LAPPING TOOL
8-14