Unheard of clutch life with Redline oil and a Rekluse Pro

I just checked the actual tolerance on the clutch pack after nearly 400 hours on an oem clutch and Rekluse Pro. The targeted range is below .050 new and optimal is in the .037 range. The starting was .038 on our 450. Well today the gap was .025. Yes it got smaller and is better than new. The redline oil actually causes the friction discs to swell ever so slightly over time and the clutch life is off the charts. This is the third bike that I have confirmed this with. Not a fluke or missed reading. The autoclutch still works flawlessly as it did when new. One of my yz450 actually got to tight and would not disengage properly. I had to install a thinner metal plate and all is good.

Just would like to add that this bike is ridden by a fast 21 y/o b rider and lots of hills and gnarly single track. The clutch and Rekluse gets a good workout.

This is just another reason why I only use Redline oil in all my bikes.

Edited by Gunner354

Aside from the plates still being in spec for thickness, how did they look? Burnt at all?

I have noticed similar sort of clutch life out of my bikes that run a Rekluse. If they are set up and ridden properly, they will basically pay for themselves in terms of clutch life after a few normal service intervals. I never have to replace a set of fibers due to them being out of spec, but more just looking burnt and noticing some slipping in the high RPM's. $70 for plates and they last a couple hundred hours or so - I can deal with that.

Edited by GHILL28

I have never used Red Line, or any other ester based, Group V synthetic. My current bike is a 2006 YZ450 that's always been run on either Amsoil MCF, MCV, or Mobil1 Racing 4T or V-Twin oils, the choice between them based primarily on the ambient temperature. All 4 of these oils are Group IV poly-alpha olefin synthetics that comply with JASO MA/MA2.

When I installed the Rekluse in late 2010, I used the existing 4 year-old OEM friction plates and the used steel set that came with the clutch. That setup lasted all of last racing season without a problem of any kind. At the end of the season, I decided to replace the steels because they were slightly scored when I got them the year before, and at the same time, my sponsor offered to buy a set of friction plates to go with it. As it happens, the now 5 year-old friction plates measure within specifications, are not blackened, and were not slipping, grabbing, dragging, chattering, or causing any other complaint on my part, but WTH, I decided to be preemptive anyway. The clutch has, at times been hot enough to cause the bike to belch smoke out of the breather in some of the tight spots the local clubs like to run us through, but it hasn't suffered noticeably for it. The clutch does work better now, but most of that is due to the fact that some of the old steels were slightly dished. I have no idea how much time was on the clutch kit when I bought it.

Frankly, the credit for long clutch life belongs to the quality of the OEM plates themselves. The Rekluse contributes to the that in that it will feather the clutch as much as necessary, but not to an excess. The oil is only a factor to the extent that it is a good, durable lubricant with the correct friction profile for a wet clutch, and esters have no particular advantage over PAO's in that regard, or for that matter a good syn/petro blend, either.

Good to know, i just got a quart of Redline full synthetic 10w-40 motorcycle specific oil, looking forward to using it.

I have never used Red Line, or any other ester based, Group V synthetic. My current bike is a 2006 YZ450 that's always been run on either Amsoil MCF, MCV, or Mobil1 Racing 4T or V-Twin oils, the choice between them based primarily on the ambient temperature. All 4 of these oils are Group IV poly-alpha olefin synthetics that comply with JASO MA/MA2.

When I installed the Rekluse in late 2010, I used the existing 4 year-old OEM friction plates and the used steel set that came with the clutch. That setup lasted all of last racing season without a problem of any kind. At the end of the season, I decided to replace the steels because they were slightly scored when I got them the year before, and at the same time, my sponsor offered to buy a set of friction plates to go with it. As it happens, the now 5 year-old friction plates measure within specifications, are not blackened, and were not slipping, grabbing, dragging, chattering, or causing any other complaint on my part, but WTH, I decided to be preemptive anyway. The clutch has, at times been hot enough to cause the bike to belch smoke out of the breather in some of the tight spots the local clubs like to run us through, but it hasn't suffered noticeably for it. The clutch does work better now, but most of that is due to the fact that some of the old steels were slightly dished. I have no idea how much time was on the clutch kit when I bought it.

Frankly, the credit for long clutch life belongs to the quality of the OEM plates themselves. The Rekluse contributes to the that in that it will feather the clutch as much as necessary, but not to an excess. The oil is only a factor to the extent that it is a good, durable lubricant with the correct friction profile for a wet clutch, and esters have no particular advantage over PAO's in that regard, or for that matter a good syn/petro blend, either.

Gray, I believe there are advantages of ester based oils over others. I'm not willing to start a negative debate though.

What I would like to know is did you actually check the specs or tolerances of the plates when you first installed the Rekluse? I would like to know if a group IV oil actually makes the friction discs swell like the ester based Redline does? If it does great, but if not then there is a huge advantage to an ester based oil. A longer clutch life might be worth it alone.

Longer than what? 5 years? At 60-80 hours per year? Save me.

The installed gap when I removed the old clutch was the same as the day I installed it, BTW.

You've attributed the service you got from your plates to the oil, but you had no control group, and no scientific basis for the assertion. Ester oils offer certain advantages, yes, but the only one that would apply to longer clutch life is the marginally better thermal stability at the extreme upper limit of the flash point. Given the longevity of my own clutch without the presumed benefits of the more expensive ester based oil, I'd have to say there's not much to it.

Whatever. I was hoping there would NOT be a condescending tone but once again I was wrong. Trying to make a valid point and ask a question at the same time but once again the moderator does not have to play by the rules.

If the cluch plates are actaully getting thicker it would make me wonder where the thickness comes from. Its not as if you are adding more friction material so it must be expanding the material thats there. Filling in the pores with oil and making them softer like a sponge.

Edited by tech857

Do the math on how much per side that is. It's about .001per side. They are NOT spongy and the clutch works as good as it did on day one. Just trying to give some good solid info for those that may care.

It would be interesting to know if group IV or group III oils do the same or some part of the additive package was the reason.

Hey gunner, is the redline oil you are talking about the third one from the left in my pic?

xt76.jpg

Well, you can swell a new clutch plate by a significant amount by soaking it in most any good premium oil overnight, or in oil heated to 150-200 ℉ for less than 2 hours. Different plate compositions will react differently, and there are a variety of reactivity issues that will come up with the various base stocks and with any number of additives. In high mileage Ford automatic transmissions that ran too long on degraded type F fluid, fresh ATF would sometimes cause complete failure of clutch plates by dissolving the embedded varnish out of the linings. PAO's have been linked to the embrittlement of certain plastics (polyoxymethylene) that are occasionally used in some engines and transmissions but it's more of a potential hazard than a conclusive cause/effect.

Esters, though are known to be incompatible with some sealing materials (principally silicon), and do cause the swelling of several kinds of seals beyond what other oils do.

The biggest advantage to esters is that they are polar in nature, and tend to bond or stick to metal parts by a kind of electrical bonding this is only really significant to a four stroke during cold starts, and it's much more important to non-rolling elements like cams and pistons. It's a much bigger deal in turbines and jet engines, though. Once oil circulation is up, though, that edge is more or less gone.

With respect to clutches in particular, a potential disadvantage of esters is its much lower native coefficient of friction. Adding 10-15% ester stock to a PAO base can reduce the friction coefficient significantly. Since JASO MA/MA2 oils (wet clutch compatible) are required to remain above a certain CoF, "ester" oils that comply with the standard are actually blends of ester and PAO.

Hey gunner, is the redline oil you are talking about the third one from the left in my pic?

xt76.jpg

Yes. Redline motorcycle specific oil has only been around a few years. Before that we ran the regular 10-40 that is on the right. It worked well also without any clutch slippage or any negative effects. I did contact Redline and they confirmed that the regular 10-40 will work with wet clutches. So my point is that it's no problem using the bottle of Redline on the right of the pic.

Edited by Gunner354

Yes. Redline motorcycle specific oil has only been around a few years. Before that we ran the regular 10-40 that is on the right. It worked well also without any clutch slippage or any negative effects. I did contact Redline and they confirmed that the regular 10-40 will work with wet clutches. So my point is that it's no problem using the bottle of Redline on the right of the pic.

Great!! that is good to know, ive been wondering about that, glad it is ok for use with a wet clutch.

...glad it is ok for use with a wet clutch.

Most, but not all, oils are OK for wet clutches. The two types that should be avoided are any oil labeled JASO MB and oils labeled API ECII (Energy Conserving 2). MB oils are engine-only oils made with added friction modifiers that make them unsuitable for clutches. These are fairly rare, made expressly for engines with crankcases separated from the clutch and trans. Honda offers one of these for the CRF's. The API ECII oils are also friction modified to an extent that could potentially cause trouble. The thing is that there are almost no (in fact none that I can think of) ECII oils made in *w-40 weight or higher, so it's not likely that you'd run into any such thing by mistake.

Thing big question is whether the oil will hold its viscosity well enough to withstand lubing the transmission. Not all of them do, but at least as far as motorcycle oils go, things are improving in that regard.

Thanks for the info grayracer513, just to be safe, i think i will exchange it for the motorcycle specific redline 10w-40.

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