9
3. Place Tappet Adjuster onto the jam nut securing the
tappet adjuster screw; then rotate the adjuster dial
clockwise until the end is seated in the tappet
adjuster screw.
4. While holding the adjuster dial in place, use the
adjuster handle and loosen the jam nut; then rotate the
tappet adjuster screw clockwise until friction is felt.
5. Align the adjuster handle with one of the marks on
the adjuster dial.
6. While holding the adjuster handle in place, rotate the
adjuster dial counterclockwise until proper valve/
tappet clearance is attained.
NOTE: Refer to the appropriate specifications in Engine/
Transmission for the proper valve/tappet clearance.
NOTE: Rotating the adjuster dial counterclockwise
will open the valve/tappet clearance by 0.05 mm
(0.002 in.) per mark.
7. While holding the adjuster dial at the proper clear-
ance setting, tighten the jam nut securely with the
valve adjuster handle.
8. Place the cylinder head cover with a new O-ring into
position; then tighten the cover securely.
KM703
9. Install the timing inspection plug.
Testing Engine
Compression
To test engine compression, use the following procedure.
1. Remove the high tension lead from the spark plug.
2. Using compressed air, blow any debris from around
the spark plug.
3. Remove the spark plug; then attach the high tension
lead to the plug and ground the plug on the cylinder
head well away from the spark plug hole.
4. Attach the gauge from Compression Tester Kit.
NOTE: The engine must be warm and the battery
must be fully charged for this test.
5. While holding the throttle lever in the full-open posi-
tion, crank the engine over with the electric starter
until the gauge shows a peak reading (five to 10
compression strokes).
NOTE: The compression should be within a range
of 210-230 psi in the full-open throttle position.
6. If compression is abnormally low, verify the follow-
ing items.
A. Starter cranks engine over.
B. Gauge functions properly.
C. Throttle lever in the full-open position.
D. Valve/tappet clearance correct.
E. Valve not bent or discolored.
F. Valve seat not discolored.
NOTE: To service valves, see Engine/Transmission -
Servicing Top Side Components.
7. Pour 29.5 ml (1 fl oz) of oil into the spark plug hole,
attach the gauge, and test compression.
8. If compression is now evident, service the piston
rings (see Engine/Transmission - Servicing Top Side
Components).
Spark Plug
A light brown insulator indicates that the plug is correct.
A white or dark insulator indicates that the engine may
need to be serviced or the carburetor may need to be
adjusted. To maintain a hot, strong spark, keep the plug
free of carbon.
ATV-0051
Adjust the gap to 0.8-0.9 mm (0.032-0.036 in.) for proper
ignition. Use a wire feeler gauge to check the gap.
! WARNING
Always wear safety glasses when using compressed air.
CAUTION
Before removing the spark plug, make sure to clean the
area around the spark plug. Dirt could enter engine
when removing or installing the spark plug.