Is there a way to tell if timing chain needs replaced?

[VTredneckgames]

In a few weeks Im going to have to have some head work done and possibly a bore (smokes heavily at WOT).

Assuming that the cam is fine, Im just going to run the stock one again. I dont want to replace the timing chain unless I really have to. On down the road I might go with a stage1 cam and I'll replace it then. But is there a way to tell if mine really needs it now? I have some ticking in the motor, but I know that most of it is in the valves.

Im basically a wuss and Im afraid of messing something up with the clutch. It works fine now and I like how it engages. I dont want to risk changing that by replacing a timing chain that I really didnt need.

Any help is appreciated. Thanks

[Which 450?]

If you know what your doing. You can tell by how far out the cam chain tensioner is. I believe it tells you how in the service manual.

[TRXRacer1]

Originally posted by Which 450?
If you know what your doing. You can tell by how far out the cam chain tensioner is. I believe it tells you how in the service manual. Other then bumping you post count that was a completely pointless post. Good Job.


Vted, with everything together, pull the auto tensioner off. When you get it off it should be fully extended or out. Fit it back in the hole and see how far in you can get it by hand. If you can go almost all the way before needing to back off the adjuster then that would indicate a good amount of stretch in the cam chain.

[rob_990]

you might as well replace it while you in there.and for the clutch..just take a sharpie and draw a line across the clutch plates/basket so you line them up correctly when you put it back together.

[TRXRacer1]

Originally posted by rob_990
you might as well replace it while you in there.and for the clutch..just take a sharpie and draw a line across the clutch plates/basket so you line them up correctly when you put it back together. Why spend the money if what he has checks out good?:confused:

[Which 450?]

Originally posted by TRXRacer1
Other then bumping you post count that was a completely pointless post. Good Job.


Vted, with everything together, pull the auto tensioner off. When you get it off it should be fully extended or out. Fit it back in the hole and see how far in you can get it by hand. If you can go almost all the way before needing to back off the adjuster then that would indicate a good amount of stretch in the cam chain.

I dont appreciate the attack. I have reported your post. There is a specific way of checking how far the cam chain has stretched. If he doesnt know how to check it nor have a manual, then he isnt mechanically inclined enough for the task.

[Which 450?]

Originally posted by TRXRacer1
Why spend the money if what he has checks out good?:confused:

This is because the stock cam chains are known for stretching easily and the heavy duty replacement, crf450 cam chain, is very inexpensive. Plus the motor will be apart, this will avoid him having to pay to have the motor re-disassemble later on.

[TRXRacer1]

Originally posted by Which 450?
This is because the stock cam chains are known for stretching easily and the heavy duty replacement, crf450 cam chain, is very inexpensive. Plus the motor will be apart, this will avoid him having to pay to have the motor re-disassemble later on. The only thing that is a stretch here is using the word "easily". There's 400's out there from 96 still running the stock cam chain. Do they stretch, sure but they aren't going to do it all of a sudden. If the chain is still good, it's still good. The only part off right now that's part of the job is the rocker box and that's the easiest part. He hasn't touched the side yet and currently has no reason until he finds otherwise.

[Which 450?]

If there's an xr400 from 96 with the stock cam chain its because it hasn't been ran hard.

[Zeb400EX]

VT
Take your tensioner out and take your valve cover off. Then look at your cam gear. Lift up your chain up off of the cam gear. If you can see the teeth on the top of the gear your chain is probably stretched. Also when my chain was wore out the motor would have this slapping sound when I would start it cold and it would go away once it got warm. Hope this helps.:)

[VTredneckgames]

Thanks for the replies.

Zeb and TRX, thanks for the tips on how to check the chain for stretch. I will do both when the time comes (probably in 2 weeks)

Which 450?, thanks for playing the devil's advocate. Someone has to. Just because I had to ask how to check it does not mean that I am not mechanically inclined enough to do it. You made a wrong assumption there. I am very mechanically inclined. However I am new to working on atvs and I am the type that likes to learn things about them. I have a cousin that works on them alot and I could easily get him to do it all for me. But I plan on doing it myself and getting his help if need be.

The clutch does worry me, that is the biggest reason I dont want to mess with it if I dont have to. I know I will have to change it at some point. I also want to put in a stage1 cam at somepoint too. So if the chain is still in decent shape, then I will wait to replace it until the time when I install the cam.

As far as having a manual, yes I do have one. However, I dont have access to it at this point in time. I just want to have all of my ducks in a row before I start. But thank you for advice nonetheless.

[F-16Guy]

My feelings are that this is an issue that is way over-hyped. I think a good deal of timing chain problems stem from improper tensioner installation. I rode the dog crap out of my 400ex for years with zero timing chain issues. In fact, the ONLY reason my stock chain isn't still on is because I had a Carrillo rod installed, so it was apart anyway. If it's properly installed, there isn't that much drag on a timing chain, even with an aftermarket cam. If you're going to have it apart for some other reason, then do it. If not, just run the stocker.

TRXRacer1 -- Which 450? had a better answer than you did. Consulting the manual for the correct procedure is better advice than your "eyeballing" method.

[TRXRacer1]

Originally posted by F-16Guy


TRXRacer1 -- Which 450? had a better answer than you did. Consulting the manual for the correct procedure is better advice than your "eyeballing" method. I'll disagree. At least I gave him something and something that will tell him a lot. Nothing eyeball about it, you're using the tensioner as a gauge. Are you trying to say that if you can get the tensioner almost all the way in with it fully extended that the chain is good? It's a dead give away test. Which 450?'s post was a total waste and contributed to a problem of stupid posts.

[Which 450?]

There is a specific measurement to test the chain. I don't know it, which is why I said to reference the book. I can out-diagnose you any day of the week btw. and I'm not being cocky, its just how it is.

[F-16Guy]

Originally posted by TRXRacer1
I'll disagree. At least I gave him something and something that will tell him a lot. Nothing eyeball about it, you're using the tensioner as a gauge. Are you trying to say that if you can get the tensioner almost all the way in with it fully extended that the chain is good? It's a dead give away test. Which 450?'s post was a total waste and contributed to a problem of stupid posts.
Okay, so exactly how far out can the tensioner extend before the chain is no good? And is the chain bad, or are the guides bad, or both? How do you tell? My tensioner didn't have any go/no-go marks on it, so I'd have to disagree with it being a guage. Without some kind of specifications or tolerances, your advice is nothing more than "eyeballing" it. Giving bad advice is worse than giving no advice. At least Which 450? indicated that he thought there was a procedure in the manual and pointed him in that direction.

[billyboy93]

i went to get my 2007 400ex serviced and they had 2 replace the timing chain and tensner so they dont last that long...its still at the shop

[TRXRacer1]

Originally posted by billyboy93
i went to get my 2007 400ex serviced and they had 2 replace the timing chain and tensner so they dont last that long...its still at the shop Consider yourself either a rare case or screwed by the service department.

[VTredneckgames]

well, I looked through the manual, but I couldnt find the right procedure. I have the pdf file. Not saying its not in there, I just couldnt find it.

I checked it like mentioned earlier, and there was about 3/16 left of travel. Some of the links looked alittle weak sideways. I figured since I had it apart, im going to go ahead and replace it. I ordered a crf450 chain for it.

[Zeb400EX]

be sure and put some lock tight (blue) on those cam gear bolts.

[TRXRacer1]

Originally posted by VTredneckgames
well, I looked through the manual, but I couldnt find the right procedure. I have the pdf file. Not saying its not in there, I just couldnt find it.

I checked it like mentioned earlier, and there was about 3/16 left of travel. Some of the links looked alittle weak sideways. I figured since I had it apart, im going to go ahead and replace it. I ordered a crf450 chain for it. Good choice, 3/16 is not enough.