hi i have a 2000 sherco 250 and the chain is comming loose nearly every trial and i dont know why i unloosen it and the pull the wheel back and it works but then the next trial it comes loose does any one know what the problem is?

thanks r.hayes

does any 1 know?

you locking the cams up?

Your chain could be whipped.

Once they are finished, they get worse real fast.

Grab the chain at 3 o'clock on the rear sprocket and try to pull it straight back.

If you can expose half a sprocket tooth(or more), you need a chain.

If you buy an o-ring, it'll probably last the life of the bike.

Also...a lot depends on where in the rotation your chain is when you check it. Chains all develop tight spots (or loose spots?) when they wear. If you adjust at a tight spot, you can spin the wheel and a loose spot can almost have your tensioner touching the swingarm. You can watch this as you spin the wheel. Again...if there's too much difference between the tight and loose spots, you need a chain.

uh i dont understand its like i tighten it up and move the wheel back and its fine untill a bit of riding the comes loose

and the cahin is in gd condition so i dont think i need a new one the cames are in the right place so i dont know

So are you saying the cams are rotating?

OK, lets back up to basics:

1) loosen axle nut

2) rotate cam adjusters located on both ends of the axle. These cams push on a solid "post" or "stop" on the swingarm. Rotating these will pull the wheel back and tighten the chain.

3) with the chain at proper "manufacturer's spec" tension, tighten the axle nuts with the cams up against the stops noted in #2.

Next time, note the position of the cams before riding, then after. If they have moved, the axle cannot be tight. If they haven't...you've got chain problems.

I had trouble with my Montesa when new but the chain was tightening up after a big hit. Cleaned up the factory grease from the sides of the cams, washers and spacers and OK. (leave the threads lubed though)

I also make sure the cams are oriented so that if they get hit with a rock they would turn in the loosening direction. Saves the chain and huge loads on the bearings.

Mark the position of your cams next ride. If the chain loosens without the axle moving then maybe time for a new chain.

By the way I found that the DID (non 0-ring) chain that I replaced the stock chain with, wore quite a bit faster then the OE chain. It was on the slightly worn sprockets though.

Flip your adjusters around so they won't get bumped.

Are you holding the axle still with an allen wrench while you tighten the nut?

the adjusters dont move the chain comes loose but the dont move a bit then i push the wheel back and tighten the nut and its fine ill the next time anyway

thanks r.hayes

Take a close-up picture of your chain and sprocket make sure you get it all including the tensioner, and post it to this topic.

i fink its the chain once ive cleaned it ill have a look

charlie c yeah my chain comes back one tooth i think need a new chain also are the snail cams supposed to be right at the end?

Dude, you need to pal up with someone who knows about bikes. The less maintainence you do the more expensive they get, and you need to keep on top of lots of things. Anew chain may well be what you need but also chain and sprockets. When the new one is installed the tension needs to be spot on, and you know you need a half link of course, probably.

SD!!!

If you can expose a whole tooth, your chain is beyond whipped.

Chances are pretty good that your worn chain has worn your sprockets in such a way that they will ruin a new chain in no time.

If you want low maintenance, get some new sprockets and an o-ring chain.

As for the half-link...I did without it on my '01. The chain fit with the axle forward.

I'm sure I'd never notice the difference in steering geometry.

hi its not a full tooth its like half heres a pic::