Spark Plug; Muffler/Spark Arrester - Arctic Cat DVX 250 2007 Service Manual

4. Attach the Compression Gauge (p/n 0644-376).
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
position, 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 200-215 psi in the full-open throttle posi-
tion.
6. If compression is abnormally low, verify the fol-
lowing 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 Section 3.
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 pis-
ton rings (see Section 3).

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.
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ATV-0051
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! 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.
Adjust the gap to 0.6-0.7 mm (0.024-0.028 in.) for
proper ignition. Use a wire feeler gauge to check the
gap.
When installing the spark plug, make 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

The muffler has a spark arrester which must be peri-
odically cleaned. At the intervals shown in the Peri-
odic Maintenance Chart, clean the spark arrester
using the following procedure.
! WARNING
Wait until the muffler cools to avoid burns.
1. Remove the cap screw (1) securing the spark
arrester (2) to the muffler assembly; then care-
fully remove the spark arrester.
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ATV0052B
KM139A
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