2007 Arctic Cat Y-12 90cc ATV Service Manual, Page 11Get this manual
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
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
! CAUTION
Before removing the spark plug, be sure to clean the area around the spark plugDirt could enter engine when removing or installing the spark plug
! WARNING
Always wear safety glasses when using compressed air
3Remove 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 hole4Attach the Compression Tester Kit (pn 0444-213)NOTE: The engine must be warm and the battery must be fully charged for this test