2007 Arctic Cat DVX/Utility 250 ATV Service Manual, Page 14Get this manual
4Attach the Compression Gauge (pn 0644-376)NOTE: The engine must be warm and the battery must be fully charged for this test ! CAUTION
Before removing the spark plug, make sure to clean the area around the spark plugDirt could enter engine when removing or installing the spark plug
5While holding the throttle lever in the full-open position, crank the engine over with the electric starter until the gauge shows peak reading (five to 10 compression strokes)NOTE: The compression should be within range of 200-215 psi in the full-open throttle position
Adjust the gap to 0.6-0.7 mm (0.024-0.028 in for proper ignitionUse wire feeler gauge to check the gap
6If compression is abnormally low, verify the following itemsAStarter cranks engine overBGauge functions properlyCThrottle lever in the full-open positionDValvetappet clearance correctEValve not bent or discoloredFValve seat not discoloredNOTE: To service valves, see Section 3ATV0052B
When installing the spark plug, make sure to tighten it securelyA new spark plug should be tightened 12 turn once the washer contacts the cylinder headA used spark plug should be tightened 18-14 turn once the washer contacts the cylinder head