Spark Plugs; Muffler/Spark Arrester - Arctic Cat 650 Twin2004 Service Manual

7. If compression is abnormally low, inspect the
following items.
A. Verify starter cranks engine over.
B. Gauge is functioning properly.
C. Throttle lever in the full-open position.
D. Valve/tappet clearance correct.
E. Valve bent or burned.
F. Valve seat burned.

NOTE: To service valves, see Section 3.
8. Pour 29.5 ml (1 fl oz) of oil into the spark plug
hole, reattach the gauge, and retest compression.
9. If compression is now evident, service the piston
rings (see Section 3).

Spark Plugs

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
plugs free of carbon.
! CAUTION
Before removing the spark plugs, be sure to
clean the area around the spark plugs. Dirt could
enter engine when removing or installing the
spark plugs.
Adjust the gap to 0.7 - 0.8 mm (0.028 - 0.032 in.) for
proper ignition. Use a feeler gauge to check the gap.
2-8
When installing the spark plug, be sure to tighten it to
1.3 kg-m (9.5 ft-lb). A new spark plug should be tight-
ened 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

The muffler has a spark arrester which must be period-
ically cleaned. At the intervals shown in the Periodic
Maintenance Chart, clean the spark arrester using the
following procedure.
Wait until the muffler cools to avoid burns.
1. Shift the transmission into neutral and set the
brake lever lock.
2. Elevate the front of the ATV on a safety stand
until the muffler is horizontal.
3. Remove the plug from the bottom of the muffler.
ATV-0051
4. Start the engine and increase RPM to "blow out"
the accumulated carbon particles.
5. Stop the engine. Wait until the muffler cools; then
install the plug and tighten securely.
! WARNING
ATV0052B
KX051A