OK - Just put a new chain on my 86' ATC250R because I thought my old chain was warn out. Turns out the chain must be fine.

After installing my new chaing and riding for less then 10 minutes it is real loose again. Then I realized that the piece that I turn to tighten the chain on the swingarm is not staying where it was. I have tightened the 2 bolts that hold the axle assembly in place. But after riding the chain loosens then I need to repeat..

So somthing must be worn out. Any ideas before I just take it in for repair?

 

well..i have this problem on my sundiro 90, the chain is loose and i can't tighten it. also, the tighteners have become useless, for some reason i can't adjust the chain.

but to your problem, how hard would it be to remove the piece you use to tighten the chain? and to replace it? not sure what it looks like, but check the threads, etc, to see if they are holding up, it could be something easy. once again, not sure how your machine is set up, but it sounds like its probably just the adjuster not doing its job anymore. sorry i wasnt much help.

 

there is a torque spec.with the adjuster.