I while back I posted about my 500 just up and dieing. Well I finally took it in after exhausting all efforts. Come to find out after rebuilding the whole thing new bearings, ect. That the chain tensioner did not get into the "groove" in the cylinder head and was not holding the chain properly. I did not realize that it had to be held into place with the cylinder head. It jumped timing by one tooth, and chewed up the tensioner. I am replacing the chain, tensioner, and gaskets. Should be good to go after that. Got pretty lucky.

Jeff

 

Thats is odd ,the strong point of the Polaris single cylinder 4 stroke is there Japanese built Fuji motors.

 

Did you remove the tensioner plug and spring and push the tensioner all the way back in to the tensioner body? Then you install the tensioner, the spring and push the plug in and tighten which then automatically adjusts to proper tension against the chain guide. Have had people just remove and replace the tensioner without resetting and have jumped sprocket teeth before. Don't know if this is your problem. Yes the top of the front stationary chain guide has a slot that it fits in in the cylinder and the bottom of the guide slips in the u shaped groove near the cam sprocket. The rear moveable guide just puts pressure on the chain from the tensioner. OPT.

 

Well, I took it apart tonight and now knowing about the half moon shape groove in the chain guide, I cant believe that I missed that the first time. Took about 30 minutes to fix. But I am getting a new guide and chain just in case it stretched something. Hey, at least I learned something without damaging anything.

Jeff