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twenty34

What Oil to Run - Synthetic or Regular?

50 posts in this topic

So you guys may have some fun with this, but perhaps someone can help me understand why a YZ's clutch would run any differently than say a CRF as it relates to motor oil used?

Don't they both pretty much run the same clutch plate materials and have a basket, inner hub, etc?

http://motocrossactionmag.com/ME2/dirmod.asp?sid=&nm=&type=news&mod=News&mid=9A02E3B96F2A415ABC72CB5F516B4C10&tier=3&nid=95F27E5564B740ABA60544EA044A5413

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from what i have read and used, a yzf's clutch has no problems with sythetic motor oils as long as it is a "motorcyle/wet clutch specific oil". The main difference between the crf and yzf clutch/gearbox is that the crfs does not share its oil with the motor, the yz does. I am not sure as to whether the crfs clutch is more tolerant towards different oils though as you can use trans specific oils or motor oil in the box. As far as i can see their 450 must be one of the few picky ones.

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I suppose, now that I know that my bike doesn't like synthetic oil, I should stop using it before I have my first clutch problem. As well as they all worked, I just assumed they were happy. But it's been 12 years (4 just on these last two). Do you think they will forgive me?

BTW, it does not have to say "motorcyle/wet clutch specific oil" (JASO MA/MA2), although that's always reassuring. They only potential problem comes from oils labeled API Energy Conserving II (EC-II). These might cause trouble. There have been specific instances where certain clutches didn't like a certain oil, but not because they were synthetic. Some YZF's would disagree with the older formulation of YamaLube, for example, and wouldn't engage smoothly or release cleanly. They didn't slip, they just didn't behave right.

This is an absolutely CLASSIC example of the technical vacuum that exists in today's MX Mags. I expect fables like this from people who don't know better, not from those in the information business. Really, seriously surprised.

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Mine doesn't like it either.... it told me so! :banghead:

There is only ONE oil to use, its Walmarts new 0W100.... Its perfect for everything.... YZF's included!

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I recommend Amsoil MCF, with Mobil 1 Racing 4T as a second choice. Most Maxima oils are also good. The only oils to truly avoid are those labeled JASO MB, and possibly API EC-II. If you use an automotive oil, change it frequently until you have a used oil analysis that shows it will stay at its rated viscosity.

http://www.thumpertalk.com/forum/showthread.php?p=2685432#post2685432

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So you guys may have some fun with this, but perhaps someone can help me understand why a YZ's clutch would run any differently than say a CRF as it relates to motor oil used?

Don't they both pretty much run the same clutch plate materials and have a basket, inner hub, etc?

http://motocrossactionmag.com/ME2/dirmod.asp?sid=&nm=&type=news&mod=News&mid=9A02E3B96F2A415ABC72CB5F516B4C10&tier=3&nid=95F27E5564B740ABA60544EA044A5413

CRF separates the engine oil from the clutch-trans oil. You can use 2 different types oil that may be better suited to the side it's on. for example motor oil in the engine and atf or twostroke gear oil in the transmission.

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CRF separates the engine oil from the clutch-trans oil. You can use 2 different types oil that may be better suited to the side it's on. for example motor oil in the engine and atf or twostroke gear oil in the transmission.
That's true, and it may be the only thing I like better about the CRF from a technical standpoint. The downside of that setup, the way it's done on the Honda , is that there's only something like 750cc of engine oil. A tiny leak can be a serious problem in short order. The 1.2L total in the YZ is little enough as it is.

The point is well taken, though. You can freely use a friction modified, JASO MB oil in the engine without worrying about the clutch, or about the oil shearing down in the trans, and use a real gear lube in the trans with the confidence it will endure such use. If Yamaha would have separated the gearbox oil and kept the dry sump lube for the engine, it would have been my idea of perfect.

But in spite of all that, there is no specific problem using any number of synthetic oils in a YZ450, or any other YZF that I'm aware of. Certain synthetic oils, maybe, but not synthetics in general, and certainly not the ones I've used.

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Hinson says not to use synthetic oils with their clutch baskets, inner hub and pressure plates.

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Hinson says not to use synthetic oils with their clutch baskets, inner hub and pressure plates.
Funny, synthetic oil didn't have any negative effect on the full Hinson I had in my '03 during the 4 years I had that.

That, frankly, is ridiculous.

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Been running Redline oil for 8 years with the Rekluse clutch with excellent results!

Lots of guys use synthetics with the Rekluse.... and they do work. I've used Motorex with mine and had decent results, but on Rekluses recommendation, I tried the Shell Rotella 15W40. The clutch works smoother and more consistant with the Shell.

With that said, I'm positive that synthetics last longer than dino's. But I think dino oil has some advantage in the clutches.... esspecially the auto-clutches.

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Funny, synthetic oil didn't have any negative effect on the full Hinson I had in my '03 during the 4 years I had that.

That, frankly, is ridiculous.

It might be ridiculous.... but I've heard that from Hinson too. I think they recommend Maxima 10W40 dino.

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The issue with oil longevity in the case of a YZF always boils down to one thing before anything else: Shear stability and viscosity retention. The problem isn't heat, or engine speed, it's the transmission.

Whether the oil is synthetic or not doesn't really have much to do with it, either. When multi-grade oils are made, the oil starts out as the lighter of the two listed viscosity numbers. A 10w-40, for instance, is built on a 10 weight base oil. A set of complex polymer additives are added in that react to heat, and keep the oil from thinning out as it heats up, so that once the 10wt base is up to 200 ℉, it's still no thinner than a straight grade 40wt at that temp.

But the molecules in these additives are large, complex, and in most engine oils physically fragile enough to be torn up and rendered ineffective by the shearing forces that occur in a gearbox. What usually ends up happening is that long before any of the advantages that synthetics have in terms of oxidization, temperature, acid resistance, etc., can show up, the trans has already turned the 10w-40 you started out with into a 10w-30, or worse.

There are 3 approaches you can take to this issue:

  • Change your oil every ride or every two hours use.
  • Use a straight grade 40wt oil. These are usually mineral oils, and so are more subject to thermal degradation than synthetics, but they have none of the viscosity index improvers added, so there are no VII's to be degraded as explained above, and will last a lot longer. Risky in cool weather if you don't allow the engine to warm up well.
  • Use an oil actually formulated for motorcycles that lube the trans with engine oil (not one that just claims to be). These use VII polymers that are created for multi-grade gear oils, which cost more, but will resist viscosity loss much better than most oils blended for automotive engines will.

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To my knowledge Redline oil does not have these additives. Group 5 polyol ester. Best basestock available to date.

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To my knowledge Redline oil does not have these additives. Group 5 polyol ester. Best basestock available to date.
The relative worth of the base stock is arguable, but if it is a multi-grade oil it will usually need VII's to accomplish that.

One thing that is true is that most truly synthetic base stocks (Group IV poly-alpha olefins and higher) have a native viscosity index that is greater than natural petroleum base oils already, so that they will need a lower percentage of VII's to meet their grade specs, but they still need it.

How much depends on how many grades they try to span. If you were to see a high grade Group IV or V oil rated at 25w-40, for instance, you might reasonably expect it to contain almost no such additives, but if it's labeled 10w-40 or 5w-40 it does, no question.

Remember that base oils for true synthetics are manufactured, and can contain whatever the blender cooks into it. Some companies will fortify the PAO or ester bases with chemistry that is nothing more than VII's and call it "base stock", even though it's really a blend already.

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Lots of guys use synthetics with the Rekluse. ... and they do work. I've used Motorex with mine and had decent results, but on Rekluses recommendation, I tried the Shell Rotella 15W40. The clutch works smoother and more consistant with the Shell.

With that said, I'm positive that synthetics last longer than dino's. But I think dino oil has some advantage in the clutches.... esspecially the auto-clutches.

Personally the longevity of my motor is way more important than how an autoclutch works. I will never run a petroleum oil in my motor because it

may make my autoclutch perform well.

Like I stated, I have used Redline with an autoclutch for years with excellent autoclutch action. I have friends that also have had excellent results. This was with the original Rekluse and the Pro version. We are using the 10-40.

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