Honda LEAD 110 2009 Service Manual page 228

VALVE SEAT INSPECTION
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.
Remove the valve and inspect the valve seat face.
The valves cannot
The valve seat contact should be within the speci-
be ground. If the
fied width and even all around the circumference.
valve face is burned
or badly worn or if it
STANDARD:
contacts the seat
SERVICE LIMIT: 1.5 mm (0.06 in)
unevenly, replace
the valve.
If the valve seat width is not within specification,
reface the valve seat (page 9-18).
Inspect the valve seat face for:
• Damaged face:
– Replace the valve and reface the valve seat
• Uneven seat width:
– Bent or collapsed valve stem; Replace the
valve and reface the valve seat
• Contact area (too low or too high area):
– Reface the valve seat
0.90 – 1.10 mm (0.035 – 0.043 in)
CYLINDER HEAD/VALVES
DAMAGED FACE UNEVEN SEAT WIDTH
TOO LOW
LAPPING TOOL
SEAT WIDTH
TOO HIGH
9-17