1997 Yamaha YFM600FWAK ATV Service Manual, Page 19Get this manual
_ Auto-Decompression Auto-Decompression of the centrifugal mechanism is used in this vehicleFrom approximately 700 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 spring
0-700 RPM