Clutch Kit Yamaha Grizzlly 4 x 4 oversized tires Jahr 2002-2009 Installation of larger tires results in taller gearing, heavier rotating mass, and a drastic negative effect on the performance of this model. This kit is designed to help restore that lost power, and bring your Big Tire Grizzly back to life. It was designed for use with oversized tires. Dalton does not currently recommend or offer a clutch kit for this model with stock tires.