Testing Engine Compression; Spark Plug; Muffler/Spark Arrester - Arctic Cat HDX CREW 2017 Service Manual

NOTE: Refer to the specifications in CHECKING

for the proper valve/tappet clearance.
 NOTE: Rotating the valve adjuster dial counter-
clockwise will open the valve/tappet clearance by 0.05
mm (0.002 in.) per mark.
E. While holding the adjuster dial at the proper clear-
ance setting, tighten the jam nut securely with the
valve adjuster handle.
3. Install the spark plug; then install the timing inspec-
tion plug.
4. Place the two tappet covers with O-rings into posi-
tion. Tighten the cap screws to 8 ft-lb.
Testing Engine
Compression
 NOTE: The engine should be warm (operating tem-
perature) and the battery fully charged for an accu-
rate compression test. The throttle must be in the
wide-open throttle (WOT) position. In the event the
engine cannot be run, cold values are included.
 NOTE: The rear seat, seat back, and seat base must
be removed for this procedure.
1. Remove the high tension lead from the spark plug.
2. Using compressed air, blow any debris from around
the spark plug.
! WARNING
Always wear safety glasses when using compressed
air.
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 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).
PSI Hot (WOT)
125-145
6. If compression is abnormally low, inspect the
following items.
A. Starter cranks engine over.
B. Gauge is functioning properly.
C. Throttle in the full-open position.
D. Valve/tappet clearance correct.
E. Engine warmed up.
F. Intake obstructed.
 NOTE: To service top-side components, see Engine/
Transmission.
PSI Cold (WOT)
100-140
7. Pour approximately 30 ml (1 fl oz) of oil into the
spark plug hole, reattach the gauge, and retest com-
pression.
8. If compression is now evident, service the top end
(see the appropriate Engine/Transmission).

Spark Plug

A light brown insulator indicates that 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.
ATV-0051
CAUTION
Before removing the spark plug, be sure to clean the
area around the spark plug. Dirt could enter engine
when removing or installing the spark plug.
Adjust the gap to 0.5-0.6 mm (0.019-0.024 in.).
ATV0052
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

Clean the spark arrester using the following procedure.
! WARNING
Wait until the muffler cools to avoid burns.
9