cam chain tensioner ????

[Gunner354]

I have an 09 and we are getting ready to rebuild after amost 400 hrs. Seems like some 08 and 09 had issues with the chain tensioner. Are these different from previous years and if so will the early versions work?

[grayracer513]

The earlier versions ('05 and prior) don't look the same, and they have different part numbers than the '06-'09 tensioner (5TA-12210-00-00 vs. 5TA-12210-10-00). A difference such as this in a Yamaha PN often indicates a revision, minor change, size difference, etc. It could be that the old ones will interchange with the new, or not. They do use the same gasket.

The '08 seemed to get the most of it, but that year was not the only one that had trouble with chains jumping. I have notice three things with regard to this:

1. ALL of the bikes I have encountered with jump time problems had tight, binding links in the chain
   
2. The new tensioner seems to have less spring load built into it than the old
   
3. Virtually none of the Gen 1 450's with the 5TA-12210-00-00 tensioner had a problem like this
   

From that, I imagined two hypotheses:

1. There is something about the Gen 2 engine that reduced the amount of oil that gets onto the cam chain
   
2. The Gen 2 tensioners are somehow at fault. This might be because they lack sufficient tension or because the resonant frequency of the spring harmonizes with some vibration it's exposed to (which seems to be reaching, but...)
   

Playing around with a leftover Gen 2 tensioner (5TA-10), I found it an easy thing to add a half turn of pre-load to the unit, and that might be of help. Don't know. Or, maybe one of the old units would fit. A side by side comparison should shed more light on that.

But then I go back to the chain and the binding, and I see that my cam chain, with twice as many hours on it as the last kinked up mess I replaced, is perfectly free and barely worn at all. So, I return to the lube question.

As you can see, I've thought some about this, but I still haven't arrived at any solid conclusions. Now you know what I know, I guess you have to go from there. But if you decide to experiment, keep me posted.

[Gunner354]

Thanks for your insight. If someone here would be willing to ship me and old Gen 1 tensioner I will figure out the difference.

I to think there is merit to a true synthetic oil.

[grayracer513]

There is merit to synthetics, of course, but the difference shouldn't manifest itself so sharply as to have all the chains using the good stuff enjoy a long and trouble free service life while the chains run on petro or blended oils all fail, or even be such that the petro oiled chains predominate in the failure column, either. I do use Amsoil MCF/MCV, and all of the engines I repaired for binding chains and timing issues had been run on petro/syn blends or Group III "synthetics", but I'm still not ready to assign that as the cause.

[Gunner354]

A true synthetic has an attraction to metal so on cold starts the chain is getting lubed very well and Dino oils may not. My 01 wr had many many hours and upon rebuild and the original chain was used. Not by my choice but a friend who bough it did not want to change it. It looked fine and appeared to have very little if any stretch.That motor only saw synthetics. I still believe there is some merit.

[grayracer513]

If you are referring to the polar attraction property, that is usually only associated with ester based synthetics. Pure polyalpha olefins such as Amsoil MCF and Mobil 1 Racing are 100% "true" synthetic based, but PAO's tend to drain off to a greater extent than esters. I'm not arguing that there is or is not an advantage to synthetics. My point is simply that if the cam chain in the YZF really is so near the edge of failure that you have to have that last bit of protection to prevent its seizing up, then there is a flaw somewhere else.

[crf450319]

I do use Amsoil MCF/MCV, and all of the engines I repaired for binding chains and timing issues had been run on petro/syn blends or Group III "synthetics", but I'm still not ready to assign that as the cause.

I've run MCF in my '09 yz450f since the second oil change with intervals every 7 hours, I replaced my cam chain at 60.9 hours and had 6 or 7 links in it that were binding.

Food for thought...

[grayracer513]

There you go. I have been tending toward the opinion that the chains themselves may be substandard and not as specified by Yamaha, which introduces a third possible root cause of the "plague".

[blakers213]

OK, got my 09 450f because of Yamaha excellent reliabilty. Now I'm scared.

[Gunner354]

Just under 400 hrs on one of my 09's without opening it up. I do use a polyol ester oil though.

Gray I agree that kinking should not happen with any oil. Are after market timing chains worth the extra money?

[crf450319]

OK, got my 09 450f because of Yamaha excellent reliabilty. Now I'm scared.

Don't be scared, there are a tonne of people who don't have issues with them, I replaced mine because it's not a hard job to do, I like to be on the "more is better" maintenance plan, and the OEM replacement chains are under $20

Are after market timing chains worth the extra money?

I was wondering the same thing, are the Pro-X cam chains any better than the OEM units ? At 3 or 4 times the cost I'd think that they're a better quality chain, but I'd like to see some empirical data. Anyone have any info ?

[grayracer513]

OK, got my 09 450f because of Yamaha excellent reliabilty. Now I'm scared.

I don't see this as something that happens to an excessively large number of YZ450's. It's more like nearly the only thing that happens to them, so I think it gets more press than it deserves. IMO, preemptively replacing the chain and tensioner should avoid the problem.

I was wondering the same thing, are the Pro-X cam chains any better than the OEM units ? At 3 or 4 times the cost I'd think that they're a better quality chain, but I'd like to see some empirical data. Anyone have any info ?

No hard data, no. But I have seen that the Pro-X is made by Borg-Warner Japan, which is certainly a reputable manufacturer.

While all of the other speculative possibilities I mentioned are still on the table, I really rather think this all has to do with a "bad batch", or a vendor change, or something. An OEM chain has always worked for me, but the Pro-X could be worth the money on a peace of mind basis.