how to tighten timing chain???

[trx400Rider]

hey guys a i need a quick answer! how do u tighten the timing chain so there isnt much slack???? please help

[ish416]

There is a cam chain tensioner, you shouldn't have to adjust it.

If there is a bit of slack it sounds like it's time to either replace the chain or the tensioner or both.

[tri5ron]

With a stock OEM tensioner, there is no adjustment.
It is spring loaded, and therefore automatically self adjusting the chain tension.

Yes, there ARE aftermarket manual adjusters,... but they are not very practical, and not highly recommended.

The stock OEM tensioner, is perfectly acceptable, and suitable for 99% of all 400ex's out there.

Your problem is most likely a stretched timing chain, which they are known for.

You need to replace the timing chain, (Preferably with a '02 crf450 timing chain).
It is also possible,...(but less likely),... that you could need to replace the tensioner too.
But again,... less likely, due to the chain has probably just stretched beyond the max range capabilities of the OEM tensioner.

If you do replace the chain,
it is highly advisable to replace the chain guides at the same time.

[trx400Rider]

Well to be honest I recently replaced the timing chain with a 2006 model crf450 chain, new guides, and tensioner. put maybe 60 hours on it since. not hard hours either, and my chain is loose. it was tight as hell when I installed everything. so Im lost..

[dxcody]

Originally posted by trx400Rider
Well to be honest I recently replaced the timing chain with a 2006 model crf450 chain, new guides, and tensioner. put maybe 60 hours on it since. not hard hours either, and my chain is loose. it was tight as hell when I installed everything. so Im lost..

60 hours is quite a bit though

[DnB_racing]

Originally posted by trx400Rider
Well to be honest I recently replaced the timing chain with a 2006 model crf450 chain, new guides, and tensioner. put maybe 60 hours on it since. not hard hours either, and my chain is loose. it was tight as hell when I installed everything. so Im lost.. it shouldn't have been (tight as hell) when new, did you release the tensioner before installing? with the adjuster installed properly its just snug not tight

[CJM]

And how many hours are on the tensioner?

They do wear out, it does happen. Id replace it every 100 hours or so if it were me.

[tri5ron]

This may or may not pertain, but I seem to recall that everyone has always suggested, when using a CRF450 chain, that it should be a '02 - '03 CRF450 chain.

He has said that he used a '06 CRF450 chain.

I don't know if they are the same from '02 to '06, and I suppose checking the part numbers for both years might answer that question,...
But just thought I'd throw that out there, just in case there IS a difference in the chains for the different years.

( I hope that makes sense, sometimes typing it out seems to make it more "corn-fuzzzin'") lol.

[powerbomb400]

With our riding that would be once a year. It should last longer than that.

[trx400Rider]

before the orginally timing chain finally gave I had around 400 hours.
When I replaced the timing chain with the crf450 chain I also replaced the guides and a new tensioner. I installed the tensioner then pulled that piece of plastic of that kept it retracted. the chain was pretty darn tight when I done that.
Its making a pretty bad tick, only when cold. but two days ago I replaced my valve cover gasket I also check the valves, just very slight adjustment was needed to be exact, so I put them in exact spec. It cant be the valves. the timing chain is loose on the cam gear.
I guess I'll have to replace it all again? Also somebody on exriders told me to use the 2006 model crf450 chain. Is anybody having problems with the 2002 model stretching so soon?

[CJM]

Before you go tearing everything apart, take the tensioner off-try and retract it with a small flathead screwdriver and see if it retracts quickly, gets stuck, etc.

I check the part numbers, everything seems the same, its the same number for 02 and 06. CRF450R.

You might not have assembled something right, you could have a bad tensioner, the valves were adjusted improperly or need to be readjusted. Or if it sounds noisy thats b/c they usually are on the xr/400ex. Mines quite noisy-but I do have a hotcam.

You replaced both guides, including the one where you must remove the clutch to do so? You totally tightened the tensioner down and then released it? The sprocket cam is on correctly and tight, cam was installed lobed DOWN, you didnt over torque the valve cover bolts, etc, etc, etc.

Double check everything.

[DnB_racing]

Originally posted by trx400Rider
I also replaced the guides and a new tensioner. I installed the tensioner then pulled that piece of plastic of that kept it retracted. maybe you did the release right but it doesnt sound like it....the way to release the tensioner,

is by removing the end plug and turning the inside with a small flat head clockwise,not by pulling the plastic guide

the way to check if tensioner is bad, is with the tensioner removed from quad, try pushing the tension shaft into the tensioner,if you can move the tensioner with you hands its bad

and with it removed try releasing with a screwdriver, but from your description above, it sounds like you tried to release the tension by pulling on the guide,not releasing the tensioner as required..

the way you tried to adjust the tension tells me your tensioner is good, but you did it wrong

the reason the chain wore was improperly adjusted tension adjustment.... and yes the 02-06 crf chains are the same

after running that tight for that long you probably also wore down the guide again,
it sounds like you dont have a service manual ...it gives all the info that would prevent these issues