Ok, I am new at this as well. I have been reading the other posts about changing the primary spring. I bought the clutch kit from HPD for my Trailblazer. It has a ton of bottom end but the top end is gone. Plus I have to buy the pipe to finish that off. But this "green" spring by itself, will it help my 400 4x2 Scrambler or do I need another color cause of 2wd? I do have a Red one from the Trailblazer. Also will it hurt the topend? And another ?. Can I get a noticable gain in power just by adding a good silencer to the 400? This bike is plenty bad, but the pipe kits are just outta my range right now. So I think just changing the spring and good silencer will be a decent inexpensive mod. The noise here in NV is not an issue, so the thing can be as loud as it wants. Any silencer suggestions will be appreciated.
Thanks.
PD

 

The easiest way to pick the correct spring is to go to your dealer, go to the parts counter and ask them to open there Polaris ATV Quick Reference Manual to the Clutch Spring Specification Chart (sorry can't remember the page number). It will show you engagement pressure and full upshift pressure. So it is very easy to choose the correct spring if you want certain characteristics. The parts guy should be able to explain it if he knows anything. Good luck and remember clutching is only complicated if you put too much thought into it. It is actually very simple but hard to explain, especially in typing.