2-5
2
NOTE: The engine should be warm (operating tem-
perature) and the battery fully charged for an accu-
rate compression test. Throttle must be in the
wide-open throttle (WOT) position. In the event the
engine cannot be run, cold values are included.
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).
6. If compression is abnormally low, inspect the
following items.
A. Verify starter cranks engine over at normal speed
(approximately 400 RPM).
B. Gauge functioning properly.
C. Throttle lever in the full-open position.
D. Valve/tappet clearance correct.
E. Engine warmed up.
F. Intake not restricted.
NOTE: To service valves, see Section 3.
7. Pour 29.5 ml (1 fl oz) of oil into the spark plug hole,
reattach the gauge, and retest compression.
8. If compression is now evident, service the piston
rings (see Section 3).
Spark Plug
A light brown insulator indicates that a 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 correct specification (see Section 1 for
proper type and gap). Use a feeler gauge to check the gap.
ATV0052
When installing the spark plug, be sure to tighten it
securely. A new spark plug should be tightened 1/2 turn
once the washer contacts the cylinder head. A used spark
plug should be tightened 1/8 - 1/4 turn once the washer
contacts the cylinder head.
Muffler/Spark Arrester
At the intervals shown in the Periodic Maintenance
Chart, clean the spark arrester using the following proce-
dure.
1. Remove the three cap screws securing the spark
arrester assembly to the muffler; then loosen and
remove the arrester.
CF105A
2. Using a suitable brush, clean the carbon deposits
from the screen taking care not to damage the screen.
NOTE: If the screen or gasket is damaged in any
way, it must be replaced.
3. Install the spark arrester assembly with gasket; then
secure with the three cap screws. Tighten to 48 in.-lb.
COMPRESSION
Model
PSI Hot (WOT)
PSI Cold (WOT)
650
125-145
100-140
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.
! WARNING
Wait until the muffler cools to avoid burns.
FOR ARCTIC CAT ATV DISCOUNT PARTS CALL 606-678-9623 OR 606-561-4983
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