I have an 02 raptor. I just rebuilt the top end with a wiseco .30 over 11:1 high compression piston along with a stage 1 hotcams. I had trouble getting it to first turn over so i bought a new battery and the problem still consists. The battery sometimes still does not have enough power to fully turn over the motor when starting. Sometimes it will just click and not turn over and sometimes it will turn over just barely enough to start it. Any suggestions? I am unfamiliar with this problem.

 

Get a better battery, not just a new one. Most recommend the battery from the Grizzly 660. (ytx20 instead of ytx14)

Rebuild/clean the starter and brushes.

Check/replace your one-way with and L&A designs aftermarket unit.

Install a manual decompression pin instead of the stock cam weights.