I recently bought a 99' Polaris Sportsman 500 that was burning oil. I had the cylinder bored out by a professional machine shop to .020 over. I also had them redo the head (glass blasted, seals replaced, guides checked, valves reseated). I then installed a new Wiseco Piston and ring set. My issue is - some times pulling the recoil the piston locks tight. At that point I can't pull the recoil any more. It locks about 10% of time, different positions, and intermittently. There doesn't seem to be any constant. I have pulled the chain taught and it doesn't seem to be the chain sticking. I also removed the piston and checked for bent rings, scratches, and everything looked good. I also measured the ring gap clearance and piston to cylinder wall clearance. Everything fit into tolerances outlined in the service manual. I can slide the piston up and down the cylinder (out of motor) without anything sticking or locking. I'm also 99% sure nothing fell into the crank case and also couldn't see anything while examining it with the cylinder off.

So I guess my question - more of an act of desperation - is has anyone else experienced this or recommend some thing for me to check?

I appreciate any help - keep rev'n and ride'n!

 

sounds like the compression is too much for you to get past. if you cant get the piston moving fast enough past the compression stroke the rope will just stop pulling. sometimes pulling it out of your hand

 

Thanks for the idea about the compression - but it's important to point out, that it locks in the cylinder even with the valve head off the motor, when assembled it locks even with spark plug removed.

 

Likely that the cage is broken for the needle bearing on the bottom end of the connecting rod. This allows the needles to roll to one spot and bind up .

 

did you replacer the roller bearing? very good point by a very good mechanic [img]i/expressions/face-icon-small-wink.gif[/img]