Crf timing chain

[0101]

Has anybody actually had trouble with the stock timing chain breaking, stretching, or skipping?

I know everybody loves the Crf chain, but im thinking the stock will be fine. I can't imagine there's a ton of load on it anyway, when compared to other parts of the engine.

[honda400ex2003]

stretching is usually the main issue with them. they stretch to where the tensioner cant take any more out and they start slapping. then they lead to skipping timing as a result. I personally have never had any issues with the stocker or the pro x one i run in mine. i ran my stocker for 5 years, the pro x is three. I dont plan to replace it again next week when mine goes together again if i pull it apart tomorrow.

imo when running a crf chain the guides need to be changed. that would be my main reason for buying a 400ex one again. my guides were still like new, but i didnt want to risk running a crf one on them and getting it caught in the old "ruts" from the 400 chain.

just my thoughts, either one will work well but for the extra reassurance the crf one is nice.

steve

[ae13291]

why not have the extra insurance of the stronger timing chain? sure the stock oil cooler is fine but dont you agree a bigger one will be better?

[0101]

Originally posted by ae13291
why not have the extra insurance of the stronger timing chain? sure the stock oil cooler is fine but dont you agree a bigger one will be better?

Of course, but this is different.
Why spend $40 on something, if the stock chain I already have is adequate?

[CJM]

Originally posted by 0101
Of course, but this is different.
Why spend $40 on something, if the stock chain I already have is adequate?

Because it wears out and stretches and then you have issues. The CRF chain does not stretch/wear nearly as easy.

Look at it like this, crack your topend open and look at the guides, they are all chewed up or your cam chain has play in it then its time to replace. If not you can leave it alone if you want. But if your doing an engine build its most wise to replace it.

Dont cry about it later if something blows, the timing chain blows you can bend valves, break the tensioner, etc which is VERY bad.

[jgar]

Originally posted by honda400ex2003
stretching is usually the main issue with them. they stretch to where the tensioner cant take any more out and they start slapping. then they lead to skipping timing as a result. I personally have never had any issues with the stocker or the pro x one i run in mine. i ran my stocker for 5 years, the pro x is three. I dont plan to replace it again next week when mine goes together again if i pull it apart tomorrow.

imo when running a crf chain the guides need to be changed. that would be my main reason for buying a 400ex one again. my guides were still like new, but i didnt want to risk running a crf one on them and getting it caught in the old "ruts" from the 400 chain.

just my thoughts, either one will work well but for the extra reassurance the crf one is nice.

steve

Do you replace the guides with new 400ex guides or are there other crf parts that have to be used?

[CJM]

Originally posted by jgar
Do you replace the guides with new 400ex guides or are there other crf parts that have to be used?

You use the 400ex guides.

[dariusld]

I did a rebuild and kept the chain that was there. Not only was it the stock chain, it was an old stock chain. 8 years later and I'm still waiting for it to break or stretch or something. I was also told to replace a perfectly good tensioner, because I was already inside the engine. Didn't listen to that great advice either. This bike is ridden very hard, always on the pipe and still intact.

IMO the heavy duty chain is overkill and a power robber.

[CJM]

Originally posted by dariusld
I did a rebuild and kept the chain that was there. Not only was it the stock chain, it was an old stock chain. 8 years later and I'm still waiting for it to break or stretch or something. I was also told to replace a perfectly good tensioner, because I was already inside the engine. Didn't listen to that great advice either. This bike is ridden very hard, always on the pipe and still intact.

IMO the heavy duty chain is overkill and a power robber.

Your one of the few exceptions Ive heard who had no issues with the chain or tensioner. These parts wear overtime, like you they might be fine-if not and the chain stretches, snaps, tensioner fails you could bent the valves or screw up the cam chain sprocket/shaft. Thats $$$, so as I look at it: Spend the money now or maybe later on you can spend 3x that.

[0101]

Originally posted by CJM
Your one of the few exceptions Ive heard who had no issues with the chain or tensioner. These parts wear overtime, like you they might be fine-if not and the chain stretches, snaps, tensioner fails you could bent the valves or screw up the cam chain sprocket/shaft. Thats $$$, so as I look at it: Spend the money now or maybe later on you can spend 3x that.

Have you had any problems with the stock chain?
So far I havent read anything from someone who actually damaged their stock chain.

Although I agree that if the chain really is that weak, the upgrade is well worth it.

[CJM]

Originally posted by 0101
Have you had any problems with the stock chain?
So far I havent read anything from someone who actually damaged their stock chain.

Although I agree that if the chain really is that weak, the upgrade is well worth it.

My buddy had issues, quad was only 5 years old and looked like it hadnt been ridden much. We drove 4 hours to get to a riding spot in PA, 10 mins in it just quit, no warning...nothing. So then we take it apart and realize the tensioner failed. Ok we replaced it, wouldnt you know it freaking failed again. So he bought a new chain and tensioner. You could easily see the old chain was stretched compared to new. He is very lucky he didnt bend the valves and damage anything else besides the chain guides.

The problem is the chain wears out, then the tensioner must push more so then it fails to. I just do not understand why people wouldnt spend the few bucks making sure it is good-cause like I said-it fails instead of spending like 100 bucks you will be spending 2-3x that on new valves, springs, possibly piston, cylinder, rod, etc.

I dont run a stock chain anymore as well, I have about 500 bucks into my engine, ill be damned if Im gonna have a 50 dollar chain fail on me and need to spend more $$$ 50 lousy bucks for the chain and 65 for a tensioner if yours is weak and of course the clutch side gasket to get to it all.

Ill make it real general: It blows cause someone didnt replace it after us experienced folk told them too, I dont want to hear about it here cause Ill laugh at them. Sorry to be so blunt but its the truth.

[ae13291]

this is not a debate weather which one is better, to each there own. it is only common sense to replace the chain if the engine is apart. i still have the stock chain in mine, am i going to tear the engine apart just to change the chain? NO i am not. but if i do tear into it for any other reason then the chain will be replaced.

[4WheelinDemon]

how could it possibly bend the valves??? i dont see how it can do that. the cam is in a fixed place by the bearings and cant wobbly around or anything. i mean yeah i can see it messing up a sproket or two but anything else i cant see how it can do that at all.

[NacsMXer]

Originally posted by 4WheelinDemon
how could it possibly bend the valves??? i dont see how it can do that. the cam is in a fixed place by the bearings and cant wobbly around or anything. i mean yeah i can see it messing up a sproket or two but anything else i cant see how it can do that at all.

If the timing chain stretches, the chain can jump teeth on the cam sprocket....changing the timing.

In the engine, the cam timing regulates the opening and closing of the valves relative to the position of the piston in its stroke. If the timing is thrown off, you can have open valves as the piston traveling upward. They smack into each other and the result = damaged piston/bent valves.

[CJM]

^ Exactly, a very COSTLY thing to happen as well!