Includes new machined inner clutch, stiffer spring and spacer. This kit will give you the hill climbing toque you need for your lifted gas Yamaha. Fits all gas Yamaha, all years. The stiffer spring keeps the clutch closed longer, resulting in lower initial gearing for climbing hills. The machined down clutch enables the belt to ride higher on the disks, lowering your gearing at takeoff. Kit does not affect top speed. Air tools (impact wrench) are required to take nut off of clutch shaft.