Hi. New member to the forum but I’ve been using it to research for a while and it seems like an awesome place. Also, I have 3 Yamaha quads so it only makes sense to finally join.

I’m doing a complete frame off restoration to a 2001 Grizzly 600. I’ve done some mods to the engine, including: Weisco 10:1 piston, bored to 635, Web Camshafts #387 grind cam, head mildly ported, header pipe welds ported, 6Sigma jet kit, DG exhaust. I probably will run 26 or 27" Mud Bugs but haven’t decided yet.

I’ve come to part of the resto where I’m going through and rebuilding the clutchs, both wet and dry systems. I’ve done a lot of research and I think I have a fairly good grasp of how to modify and how the cvt system works. One thing I haven’t been able to find is the rate of the stock secondary spring and how it compares to the after market EPI spring colors.

Does anyone here know what the stock rate is? Which EPI spring would be a step up from stock or if you have a color recommendation that would be appreciated.

Edit: I’m not an overly aggressive driver but the quad will seem some mud, heavy pulling, and slow going in rough terrain. I like to have fun but it will also be worked hard on occasion.