Do you set the timing chain tensioner the same way you do it on a 300ex? cause the tensioner looks a little different from a 300ex.
The quad is bone stock except for a UNI filter.
Im goin to get a repair manual tomarrow.
Hey, thanks for all the help guys its much appreciated.

 

The manual will pay for itself many times over so thats a good choice.

If you want to reset the tensioner before you get the manual its pretty easy too.

Remove the screw (phillips head) from the tensioner to expose the internals etc. The manual will tell you to either purchase some tool or fabricate one (at least the oem one does) but you can reset it with one of the smaller flat or common screw drivers (like the free ones many companies hand out that have the little clips for your pocket etc). Once you have a proper sized driver just slowly turn the inner shaft clockwise which will release the pressure on the chain, and then release the driver and the adjuster should return (quickly) and reapply the pressure.

This really isnt a good way to check if the chain is stretched but will tell you if there was a problem with the adjuster.

A trick that seems to work with checking for a bad chain requires removing the adjuster completely (dont forget you will possibly need a new gasket) letting become fully extended and then trying to fit it into its proper place (this is not how to re install it just to check) and if it comes close to or will let you set it up to the back of the cylinder where it mounts then most likely the chain will need replacing. I know a couple of atv mechanics that use this method so have to think its close if not accurate, and when I have checked mine just to see how well this works etc it has not come close to touching even with a good amount of muscle etc, and the chain has checked out ok during tear down as well. So be cautious but its something you can try.

 

Hey,
thanks alot for the help, I'm going out to work on the quad tonight, Ill let you know how it goes.

 

The tapping noise is metal smacking off the timing chain from the front guide that keeps tension on the timing chain, buy a new one. Had the same problem. Good luck!!!

 

Do you mean to buy a new chain or guide?

 

Buy a new guide they're pieces of metal coated with rubber. Once you rub through or it wears off youll here tapping.

Buy new guides!!!

 

Agreed [img]i/expressions/face-icon-small-smile.gif[/img]

 

when i rebuilt my top on my 400ex end we put it all back togather and it was making a tapping noise as weel we had put it togather a few times and thought we were pros at timing it, after we put it all back togather it was making a tapping noise we were positive it wasnt the timing cause we had done it a thousand times and never had this problem, so we took it all apart and to our amasement it was one tooth off, but it all back togather and no more tappin. just my two cence

wreckless

 

wreckless400ex
Is it possible you tore it down and timed it without putting gaskets back on until you found it was a tooth off?

The reason is I ask this is because that would add height to the head and that would tighten the chain and possibly change the position of where the guide rubs up or down a couple mills.


PualV
Have you figured out what is wrong?

The best thing you could do is check the auto tensioner to see if it's working, check the guides to see if their showing metal, and check the chain last to see if it's loose. If you can move the chain at all away from the cam it's loose, get it tightened. If you need help on how to do any of this let me know.

 

[quote]
Originally posted by: vd
wreckless400ex
Is it possible you tore it down and timed it without putting gaskets back on until you found it was a tooth off?

The reason is I ask this is because that would add height to the head and that would tighten the chain and possibly change the position of where the guide rubs up or down a couple mills.

No it was just one tooth off, it was one tooth forward so we moved it one back, we didnt think it would cause the noise either, could be a different noise, i dunno i was just tellin my story to see if it was possibly the same thing.

Wreckless