9
GZ059
4. Install the spark plugs and timing inspection plug;
then remove the cap screw from the crankshaft and
install the crankcase end cap.
NOTE: Apply grease to the end cap to aid in instal-
lation.
5. Place the two tappet covers into position making sure
the proper cap screws are with the proper cover.
Tighten the cap screws securely.
Testing Engine
Compression
NOTE: The engine should be warm (operating tem-
perature) and the battery fully charged for an accu-
rate compression test. In the event the engine cannot
be run, cold values are included.
NOTE: On the X, the seats and rear body panel
must be removed and the radiator tilted rearward for
this procedure.
NOTE: On the 4X, the rear seats and rear body
panel must be removed and the radiator tilted rear-
ward for this procedure.
1. Remove the high tension lead from the spark plugs.
2. Using compressed air, blow any debris from around
the spark plugs.
3. Remove the spark plugs; then attach the high tension
leads to the plugs and ground the plugs on the cylin-
der heads well away from the spark plug holes.
4. Attach the Compression Tester Kit.
5. While holding the throttle in the full-open position,
crank the engine over with the electric starter until
the gauge stops climbing (five to 10 compression
strokes). Compression should be 190-220 psi.
NOTE: If the throttle is not held in the full-open
position, compression reading can be low.
6. If compression is abnormally low, verify the follow-
ing:
A. Battery is fully charged and in good health.
B. Starter cranks engine over (normal speed).
C. Gauge is functioning properly.
D. Throttle in the full-open position.
E. Valve/tappet clearance correct.
F. Engine warmed up.
G. Intake not restricted.
NOTE: To service top-side components, see
Engine/Transmission.
7. Pour approximately 30 ml (1 fl oz) of oil into the
spark plug holes, reattach the gauge, and retest com-
pression.
8. If compression increases to normal, service the top
end (see Engine/Transmission - Servicing Top-Side
Components).
Spark Plugs
A light brown insulator indicates the plug and fuel/air
ratio are correct. A white or dark insulator indicates that
the engine may need to be serviced. To maintain a hot,
strong spark, keep the plug free of carbon. Adjust the gap
to 0.5-0.6 mm (0.019-0.024 in.).
ATV-0051
ATV0052E
! WARNING
Always wear safety glasses when using compressed
air.
CAUTION
Before removing a spark plug, be sure to clean the area
around the spark plug. Dirt could enter engine when
removing or installing the spark plug.