2006-2008 Polaris Snowmobiles FS/FST Service Manual., Page 59Get this manual
Maintenance PVTDRIVE SYSTEM MAINTENANCE
Drive Belt Deflection
1234Measure the belt deflection with both clutches in their full neutral positionPlace straight-edge across the clutches, and on top the beltPull the belt down and measure the distance between the straight-edge and top of beltThe measurement should be no more than 14" (3.2cm)
Chaincase Chain Tension