I ran into Larry Frederick Michigan WSA race director two seasons ago in Newberry; he had a new 01 Sno Pro that had a killer helix, so he said. I figured I need to do something to keep up with my buds new F7, so I just ordered a billit 57/55 helix from BM for my 2000 ZR440. What's in store for me. Will I have to remove the clutch off the sled to replace. I'm not sure how to do this. Tips would be great.