Honda WB20XT2 Manual page 105

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CYLINDER HEAD
VALVE SEAT WIDTH
Remove the carbon deposits from the combustion
chamber (page 3-9).
Inspect each valve face for irregularities.
If necessary, replace the valve.
Apply a light coat of Prussian Blue or erasable felt-
tipped marker ink to each valve seat.
Insert the valve, and snap it closed against its seat
several times. Be sure the valve does not rotate on the
seat.
The transferred marking compound will show any area
of the valve face that is not concentric.
Measure the valve seat width of the cylinder head.
WB20XT2:
STANDARD:
IN/EX: 0.70 – 0.90 mm (0.028 – 0.035 in)
SERVICE LIMIT:
IN/EX: 2.0 mm (0.08 in)
WB30XT2:
STANDARD:
IN:
EX:
SERVICE LIMIT:
IN/EX: 2.0 mm (0.08 in)
If the measurement is more than the service limit,
recondition the valve seat (page 12-10).
Check whether the valve seat contact area of the valve
is too high.
If the valve seat is too high or too low, recondition the
valve seat (page 12-10).
VALVE GUIDE I.D.
Ream the valve guide to remove any carbon deposits
before measuring the guide I.D. (1).
TOOL:
Valve guide reamer 5.510 mm (2) 07984-2000001
• Turn the valve guide reamer (special tool) clockwise,
never counterclockwise.
• Continue to rotate the special tool while removing it
from the valve guide.
12-6
0.70 – 0.90 mm (0.028 – 0.035 in)
0.90 – 1.10 mm (0.035 – 0.043 in)
WB20XT2•WB30XT2
VALVE LAPPER
(Commercially available)
TOO LOW
VALVE SEAT
WIDTH
TOO HIGH
(2) HANDLE
(Commercially
available)
(1)