Honda Metropolitan CHF50 Service Manual page 65

MAINTENANCE
ADJUSTMENT
Shift the rocker arm to the spring side and remove
the shim.
NOTE:
• Do not allow the shims to fall into the crankcase.
• Mark all shims to ensure correct reassembly in
their original locations.
• The shims can be easily removed with tweezers
or a magnet.
Clean the valve shim contact area with compressed
air.
Measure the shim thickness and record it.
NOTE:
• Sixty-nine different shim thicknesses are avail-
able in increments of 0.025 mm (from 1.200 mm
to 2.900 mm).
SHIM
Calculate the new shim thickness using the equa-
tion below.
A = (B-C) + D
A: New shim thickness
B: Recorded valve clearance
C: Specified valve clearance
D: Old shim thickness
• Make sure of the correct shim thickness by mea-
suring the shim with a micrometer.
• Reface the valve seat if carbon deposits result in
a calculated dimension of over 2.900 mm.
Install the newly selected shim on the valve retainer.
Rotate the camshaft by rotating the drive pulley
(crankshaft) counterclockwise several times.
Recheck the valve clearance.
Install the following:
- Cylinder head cover (page 8-22)
- Belt case cover (page 9-5)
- Radiator cover (page 6-8)
9 8 0 9
1.80 mm 1.825 mm 1.85 mm 1.875 mm
3-9