I am having a problem with my timing chain falling off the bottom sprocket. I have put it back on once and it fell off again almost immediately. I have checked the spring on the chain tensioner and it seems ok.

I have recently installed a big bore kit and when reinstalling I came up short on one of the bolts on top of the head at the cam, I know this was stupid but I ran it without it, my dealer was taking forever to get the bolt in and I'm still not sure if it is in yet. I really don't think it is the cause of the problem being it's coming off on the bottom sprocket but I wanted to include everything I know. The cam also has a tiny bit of play in it but not much.

I am pretty famailiar with the top end but am almost clueless to the bottom. I'm sure if I know what the problem is I can get in there and fix it though. I know I can take it to a dealer and get it fixed but I would rather do it myself so any information would be GREATLY appreciated. Thanks for your replies.

 

not sure if this would be the problem but i had a 87 trx250x and the cam chain tensioner was shot the chain stayed on but made lots of noise and it always seemed to go thur the tensioners like every 2 to 3 years i suppose the dealer did not get something together rite or maybe in my case something was like slitely bend or misallined... hope i was some help.....

 

Thanks Hesston1, that could of been my problem but my chain tensioner is tight so I have come up with the conclusion that my timing chain has stretched. I hope a new chain is all it needs cuz I'm ready to get some riding in as soon as it warms up. Thanks for all the help.