2008 Arctic Cat DVX 250 / 250 Utility ATV Service Manual, Page 13Get this manual
7While holding the adjuster dial at the proper clearance setting, tighten the jam nut securely with the valve adjuster handle8Place the cylinder head cover with new O-ring into position; then tighten the cover securely BGauge functions properlyCThrottle lever in the full-open positionDValvetappet clearance correctEValve not bent or discoloredFValve seat not discoloredNOTE: To service valves, see Section 3
7Pour 29.5 ml (1 fl oz) of oil into the spark plug hole, attach the gauge, and test compression8If compression is now evident, service the piston rings (see Section 3)
Spark Plug
9Install the spark plug; then install the timing inspection plug
Testing Engine Compression
To test engine compression, use the following procedure1Remove the high tension lead from the spark plug2Using compressed air, blow any debris from around the spark plug
A light brown insulator indicates that the plug is correctA white or dark insulator indicates that the engine may need to be serviced or the carburetor may need to be adjustedTo maintain hot, strong spark, keep the plug free of carbon