1998-2001 Yamaha YFM600FHM Grizzly Factory Service Manual, Page 107Get this manual
COMPRESSION PRESSURE
COMPRESSION PRESSURE MEASUREMENT IANoSJP 1(.0) 1
MEASUREMENT NOTE:
Insufficient compression pressure result in loss of performancewill
1.Check: Valve clearance AdjustOut of specification Refer to "VALVE CLEARANCE ADJUSTMENT"2.Start the engine and let it warm up for several minutes3.Stop the engine4.Remove: Spark plug 5.Attach: Adapter Compression gauge CD