Timing chain rattles. What to do

[wv400ex]

I have a 2000 400 ex and the timing chain is rattling pretty bad on it. Is there any way to tighnten it up any or not? Please does any body know. Thanks.

[miken]

I believe your 400ex has an automatic style cam chain tensioner. No adjustment. Either the tensioner is not working or your cam chain has stretched beyond the adjustability of the tensioner.
Mike -

[wv400ex]

IS there any way to tell if the chain is shot or not?

[cals400ex]

i would remove the timing chain tensioner. then put the tensioner back in its position without retracting it. if you can put it all the way back in and you don't feel the tensioner hitting the chain, its stretched too much. if you put in, you should feel the tensioner hitting the chain before the tensioner hits the metal on the head where it mounts.

[wv400ex]

Ok thanks I will try that.

[balls2da-wall]

If your quad feels like it is running like junk...then more than likely it has streched the chain...400ex's are know for streching chains!!! If you took the valve cover off you could get a better look at the chain cause I know it's a pain in the butt taking that tensioner off and getting it back in right!!!:p

[markk]

The chain a a self adjuster on it, And if its clattering, Unscrew your tensioner, and see how much it pops out, and then if u have 1/4inch or less u need to replace the timing chain!!!!, or see if the tensioner moves at all!