Valve Seat Inspection/Refacing - Honda SH300 2006 Manual

Ream the new valve guides.
Use cutting oil on
Insert the reamer from the combustion chamber
the reamer during
side of the cylinder head and always rotate the
this operation. Take
reamer clockwise.
care not to tilt or
learn the reamer in
TOOL:
the guide while
Valve guide reamer, 4.5 mm
reaming.
Clean the cylinder head thoroughly to remove any
metal particles after reaming and reface the valve
seats (page 9-16).

VALVE SEAT INSPECTION/REFACING

INSPECTION
Clean the intake and exhaust valves thoroughly to
remove carbon deposits.
Apply a light coat of Prussian Blue to each valve
seat.
Tap the valve against the valve seat several times
without rotating the valve, to check for proper valve
seat contact.
Remove the valve and inspect the valve seat face.
The valve cannot be
The valve seat contact should be within the speci-
ground. If the valve
fied width and even all around the circumference.
face is burned or
badly worn or if it
STANDARD: 0.90 – 1.10 mm (0.035 – 0.043 in)
contacts the seat
SERVICE LIMIT: 1.5 mm (0.06 in)
unevenly, replace
the valve.
If the seat width is not within specification, reface
the valve seat.
Inspect the valve seat face for:
• Damaged face:
– Replace the valve and reface the valve seat.
• Uneven seat width:
– Replace the valve and reface the valve seat.
07HMH-ML00101
HAND-LAPPING TOOL
DAMAGED FACE
CYLINDER HEAD/VALVES
VALVE GUIDE
REAMER
SEAT WIDTH
UNEVEN SEAT WIDTH
9-15