Honda 2009 CRF450X Owner's Manual & Competition Handbook page 76

Valve Clearance
Shim Selection
1. Clean the shim contact area in the valve lifter
(1) with compressed air.
(1)
(1) valve lifter
70
Servicing Your Honda
HONDA O/M CRF450X (Eu) 3RMEY620 00X3R-MEY-6200
2. Measure the shim thickness with a micrometer
and record it.
Seventy-three different thickness shims (2) are
available from the thinnest (1.200 mm
thickness) shim to the thickest (3.000 mm
thickness) in intervals of 0.025 mm.
(2)
(2) shim
3. 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
• Make sure of the correct shim thickness by
measuring the shim with a 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.
180 182 185 188
1.80 mm 1.825 mm 1.85 mm 1.875 mm