Just wondering if there would be a huge difference between a 168/312 and a 165/310 primary spring. Another question is that when I hole shot and dont hook up its like it stops shifting and has a slight bog and when I regain traction the clutch starts to shift again and takes right off. its like the secondary shifts to fast and pulls the rpm's down but when I roll on start there is no problem. Its not a big bog but enought to loose the hole shot if I dont hook up good. Any Ideas as to what the problem might be.

just a start, check belt deflection??????

I am having the EXACT same problem w/ my 99' 600! :( I was told by either zrt800 or zr sled head to put another rotation on my helix, or go w/ a stiffer spring, I have not tried it yet (been working on my trucks) but if you figure it out either email me or post what u did K thanx Rick

What is a rotation on a helix? Going to a different first number or actually moving the helix? Thanks.

when the track spins, the clutch's think your sled is speeding up and shifts accordingly, but when it regains traction is sounds like your sleds are not backshifting, you might try tightening up the sec. spring a hole or two or maybe trying a different helix. the better thing to go would be to make it so it doesn't spin, but sometimes thats harder than it sounds