1998-2001 Yamaha YFM600FHM Grizzly Factory Service Manual, Page 49Get this manual
Auto-Decompression Auto-Decompression of the centrifugal mechanism is used in this vehicleFrom approximately700 rmin, the governor's weights CD are pulled inward by the springs and causes the decompression lever to turn clockwiseAs result, the pin in the decompression lever is forced up and the exhaust valve's rocker arm is pushed and compression is slightly releasedWhen engine revolution exceeds 700 rmin, the weights are forced out causing the decompression lever to turn counterclockwiseThe pin is then forced down by the spring0-700 RPM 700 RPM-
Cam surface