Honda CRF450R Owner's Manual page 36

4. SERVICE AND MAINTENANCE
Shim Selection
Clean the valve shim contact area in the valve lifter with
compressed air.
(1) VALVE LIFTER
Measure the shim thickness and record it.
NOTE:
• Seventy-three different thickness shims are available
from the thinnest (1.200 mm thickness) shim to the
thickest (3.000 mm thickness) in intervals of 0.025
mm.
(1) SHIM
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Calculate the new shim thickness using the equation
below.
A = (B – C) + D
A: New shim thickness
B: Recorded valve clearance
C: Specified valve clearance
D: Old shim thickness
NOTE:
• Make sure of the correct shim thickness by measur-
ing the shim with the micrometer.
• Reface the intake valve seat if carbon deposits
result in a calculated dimension of over 2.450 mm.
Reface the exhaust valve seat if carbon deposits
result in a calculated dimension of over 3.000 mm.
Camshaft Holder Assembly Installation
Install the newly selected shims on the valve retainers.
CAUTION:
• Do not let the shims fall into the crankcase.
(1) VALVE RETAINERS (2) SHIMS
Apply molybdenum disulfide oil (a mixture of 1/2 en-
gine oil and 1/2 molybdenum disulfide grease (contain-
ing more than 3% molybdenum disulfide additive)) to
camshaft and outer surface of the each valve lifters.
Install the valve lifters into cam shaft holder assembly.
(1) CAM SHAFT HOLDER ASSEMBLY
(2) VALVE LIFTERS