2-22 PERIODIC MAINTENANCE
Periodic Maintenance Procedures
Using the thickness gauge [A], measure the valve clear-
ance between cam and valve lifter.
Exhaust 0.22 ∼ 0.31 mm (0.0087 ∼ 0.0122 in.)
0.15 ∼ 0.21 mm (0.0059 ∼ 0.0083 in.)
Each piston has two intake and two exhaust valves.
Measure these two intake or exhaust valves at the same
Check the valve clearance using this method only.
Checking the clearance at any other cam position may
result in improper valve clearance.
Valve Clearance Measuring Position
#1 Piston TDC at End of Compression Stroke:
Intake valve clearances of #1 piston, and
Exhaust valve clearances of #1 piston
#2 Piston TDC at End of Compression Stroke:
Intake valve clearances of #2 piston, and
Exhaust valve clearances of #2 piston
If the valve clearance is not within the specified range,
first record the clearance, and then adjust it.
Valve Clearance Adjustment
To change the valve clearance, remove the camshaft
chain tensioner, camshafts and valve lifters (see the
Engine Top End chapter). Replace the shim with one of
a different thickness.
Mark and record the locations of the valve lifters and
shims so that they can be reinstalled in their original
To select a new shim which brings the valve clearance
within the specified range, refer to the Valve Clearance
Apply a thin coat of molybdenum disulfide grease to the
Install the camshafts. Be sure to time the camshafts prop-
erly (see Camshaft Installation in the Engine Top End
Remeasure any valve clearance that was adjusted.
Readjust if necessary.
Do not put shim stock under the shim. This may
cause the shim to pop out at high rpm, causing ex-
tensive engine damage.
Do not grind the shim. This may cause it to fracture,
causing extensive engine damage.