Blue Plates

[teamtoxic]

<font color="navy">Today I went riding, and attempted to drag race my Dad's 2 day old KTM 520 EXC but that proved to be impossible. I've had the grabbiness that virtually all 2000 YZ 426's have had but its began to become a real problem. It got to the point that it was difficult to get moving and drag racing was completely out of the question. ITS REAL BAD.

When I got home, I power washed, changed oil, cleaned air filter, etc. and took out my clutch basket. To my amazement, the basket looks just fine! Nothing wrong with the basket at all. However, the steel clutch plates are blue in color, indicating that it must have become very hot at some point. Has anyone experienced this before? Surely this can't be normal. Also, the very last friction plate had some wear on it.

No matter what, I will be purchasing new friction and steel plates. Do you think that my grabby clutch could be cured with new plates and just the 2001 upgrade parts?

I'm using Mobil 1 synthetic, 20W40. I live in Michigan, riding temperature average is about 70 degrees. I'm thinking that possibly the synthetic oil is causing TOO much clutch slippage, thus; my heated blue plates.

I know that simply buying everything new would solve the problem, but I'd rather not throw that kind of money into it if its not necessary. I'm 16 so big money doesn't come real easy. You've been there before!

Thank you all! ?

this message board kicks!</FONT>

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~~~~~YaMaHaFoUrTwOsIx~~~~~

[This message has been edited by teamtoxic (edited 05-20-2001).]

[elroyona426]

If your clutch is grabby wouldn't that mean that it engages real quickly? Meaning that you could get moving?

[dirtdad]

I can offer you some experience here in regard to the upgrade. I re-did my clutch about a month ago with the updated parts in addition to a Hinson basket and inner hub. My clutch is buttery smooth now! I only have about 4 hours on it with updated parts, so I guess it really hasn't withstood the test of time. It operates flawlessly so far though. I must also add that I really don't use the clutch a whole lot. Just on starts, upshifts and the rare stall prevention in real tight turns. Hope this helps.

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00 YZ426F

01 TT-R125L (my son's)

91 CR125

83 YZ490

74 Hodaka Super Combat(gone but not forgotten!)

[enmerdeur]

Originally posted by teamtoxic:

<font color="navy">

I'm using Mobil 1 synthetic, 20W40. </FONT>

I believe the 20W40 has friction modifiers in it which is a no no. You want to use the Mobil 1 15W50 which has none of the modifiers.

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SHN

99'YZ-400 (Mine)

00' TT-R 125 (Hers)

91' KX-125 (Son #1)

93' CR-80 (Just sold it. Looking for another TTR125 for Son #2)

99' PW-80 (Son #3)

[teamtoxic]

<font color="navy">Well I solved my problem guys. I know its only a temporary fix but my family and I have had plans for memorial weekend, so I went ahead and did what I could with what I had.

I've decided that I will order a Performance Engineering clutch basket and new Barnett plates. I've talked to a few highly knowledgable people about the 2001 update parts and they seem to agree that the parts aren't necessary and that the harder clutch basket material will prevent this from happening again.

Here was what I did:

After further inspecting my clutch basket, I could notice VERY SLIGHT wear, so I filed the clutch fingers completely smooth. I then lightly sanded(400 grit sandpaper) all of my plates, both friction and steel. I rearranged the friction plates and turned them around so the opposite side hits the clutch fingers than did before. I put it back together, and used 1700mL of Mobil 1 10W-30 tri-synthetic oil.

I started it up and let it run for a few minutes.

Engagement was very smooth, as smooth as a new 250 two stroke. What a relief.

Now, I do know that this is only a TEMPORARY fix, and I will be ordering the PE basket and Barnett clutch plates tomorrow. The parts would not make it in time for me to install them before the weekend, so I will when I return.

One more thing, my Dad decided since he just spent big bucks on his 2001 KTM 520 EXC, that he'd help me out paying for the stuff I need. ?

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~~~~~YaMaHaFoUrTwOsIx~~~~~

[enmerdeur]

Unless you use the Mobil 1 15W50 you are probably going to fry your clutch again. All the other Mobil 1 Automotive synthetics have friction modifiers that will cause slipage. I highly suggest you change your oil before you ride.

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SHN

99'YZ-400 (Mine)

00' TT-R 125 (Hers)

91' KX-125 (Son #1)

93' CR-80 (Just sold it. Looking for another TTR125 for Son #2)

99' PW-80 (Son #3)

[This message has been edited by enmerdeur (edited 05-20-2001).]

[YZ426_Kicks]

Hey Teamtoxic!

...Heads up...

When I was talking with Brian Hinson on my YZ clutch issue, he told me that the KTM was developing the same grabbiness and clutch issues that plagued the 2000 YZ. They are really researching it because just as you found out, nothing seems to be wrong, yet the clutch packs are burnt.

You may want to call them. Go to www.hinsonracing.com

Thanks!

Best wishes!

Randy

YZ426 Kicks!

[Dave_S]

On my 00 426, I went through a similar proceedure, I removed and filed/emery clothed the basket smooth although it was not very grooved. I re-assembled it and it seemed to work pretty good, no grabbiness for a couple of rides. It DID come back.

I was going to order a Hinson basket and install it but since the stock basket really didnt look bad at all I figured I would try cleaning it up real good and try it again, I unfortunatly dropped and broke the basket during the clean up process.. Oh well.

I overnited and installed the Hinson basket (using the stock inner hub still) and the clutch is MUCH better but I still have grabiness. The basket did not cure the problem entirely. It did however help a lot. I have the 01 parts on order but they are not in yet. It would seem that they are in fact important.

I also intend to use a MSR raptor clutch lever to lengthen the friction point as my clutch really seems to by pretty much a 'light switch'

Dave S

[teamtoxic]

<font color="navy">Alright guys, listen to me on this one! My Dad just got off the phone with the mechanic at the dealership that we bought his KTM 520 EXC from. This guy is VERY knowledgable, he's worked on bikes forever, gone to numerous seminars and REALLY KNOWS HIS STUFF.

In the KTM manual, it says to use a synthetic oil, however this mechanic went to a seminar on clutching and he has nothing good at all to say about synthetic oils. Despite what the manuals say, on these four strokes that share oil between top and bottom ends, he says to use a regular grade oil. No synthetics. He's talked to many people that have destroyed multiple clutches using synthetics then when they switch to a non-synthetic, they've had NO MORE PROBLEMS.

What happens with(most) synthetics is it allows the clutch to slip TOO much, creating heat. This combined with the dry sump oil system of the 426 and all that torque, is very hard on the clutch.

Needless to say, I'm draining this crap synthetic and I'm going to start running non synthetic. I'm sure many of you out there may swear by the synthetics , but I'm going to try the non synthetics for a while and see how that goes.

The mechanic swears by the non synthetics, and he would not give us some bull crap story, as we've sold 3 KTMs for him in the last week by recommending him to friends. He wants our business and loyalty.

Oh and I ordered my clutch basket and new plates. I spoke with another highly knowledgable person and he said the upgrade parts are not necessay and that the harder clutch will cure the problems. We'll see, if the problems are not cured, then I'll order those 2001 upgrade parts.

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~~~~~YaMaHaFoUrTwOsIx~~~~~

[This message has been edited by teamtoxic (edited 05-21-2001).]

[enmerdeur]

Again the issue is not if you use synthetic or non-synthetic. If either has friction modifiers in them they will fry the clutch. That is why I only use the Mobil 1 15W50 because it does not contain the modifiers and it is half the price of Yamalube.

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SHN

99'YZ-400 (Mine)

00' TT-R 125 (Hers)

91' KX-125 (Son #1)

93' CR-80 (Just sold it. Looking for another TTR125 for Son #2)

99' PW-80 (Son #3)

[dirtdad]

Actually, the question apprently is whether any of us have the "credentials" to answer any of these questions. Toxic, I myself or any of the other members here obviously don't work on bikes for a living, but we are sharing info with you based on our own EXPERIENCE with the issues that YOU had questions for. If you weren't planning on accepting anything we have to offer, why ask the questions? Again, I have the updated clutch parts in my 00 426 and I've definitely noticed an improvement. My clutch operates flawlessly without ANY grabbiness! Over the past 10 months I've read countless posts by members who have installed the Hinson basket and noticed an improvement, but STILL experience a noticeable grabbiness in the clutch. But again, none of us apparently are "highly knowledgable experts". Best of luck.

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00 YZ426F

01 TT-R125L (my son's)

91 CR125

83 YZ490

74 Hodaka Super Combat(gone but not forgotten!)

[enmerdeur]

Well said dirtdad.

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SHN

99'YZ-400 (Mine)

00' TT-R 125 (Hers)

91' KX-125 (Son #1)

93' CR-80 (Just sold it. Looking for another TTR125 for Son #2)

99' PW-80 (Son #3)

[John_H]

Hey,

I've never used synthetic oil in any of my bikes (streetbikes for the past 20 years), nor in any of my cars and trucks. Always seemed kind of pricey to me with no solid data (that I know of) that its "better". From what I read, synthetics keep their lubricating qualities longer, but at $3.20 a quart for Yamalube, I don't mind frequent oil changes for my WR.

John Hamilton

[This message has been edited by John H (edited 05-22-2001).]

[YZmann]

Teamtoxic, ignorance is bliss. Did your dad's CR500 ever have a clutch problem, I think not (wasn't Mobil One run in it). Synthetics have been used in wet clutches for years, I have NOT seen one scientific study that has shown a problem. If you want to do a test, take your old clutch pack, soak it in Mobil One, fling excess off. Then re-assemble clutch on bench, using OLD basket fastened to bench through holes you removed old gear from. Fab up a spider assembly with tubes to slide in the spring holes and a nut welded in the middle, place a torque wrench on nut and measure ft/lbs of torque required to break free. You'll find it far exceeds the torque your bike is capable of. Think about it, oil did not cause basket to indent. A YZ426's dry sump results in a lot less oil for cooling the clutch, not to mention a 4-stroke generates much more heat in the oil then a 2-stroke (which uses it only for trans). It's cheaper to replace clutch plates than rebuild an engine. I think KTM engineering knows more than that mechanic does.

[teamtoxic]

<font color="navy"> Well guys, thanks for the replies. I'm not ignoring what you have to say by any means, but the more and more research that both my Dad and I have been doing, the more and more I keep learning. I've thought about what each and every one of you have told me. I'm only trying to inform you all of what I have learned too. I'm going to experiment with all of this information and see what works best.

Thank you all for your responses

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~~~~~YaMaHaFoUrTwOsIx~~~~~

[teamtoxic]

Originally posted by enmerdeur:

Again the issue is not if you use synthetic or non-synthetic. If either has friction modifiers in them they will fry the clutch. That is why I only use the Mobil 1 15W50 because it does not contain the modifiers and it is half the price of Yamalube.

<font color="navy">Thanks enmerdeur, I'll take your advice on that. That does make sense. Do the friction modifiers create more friction or less friction? I'm assuming less friction because it is automotive oil.

[enmerdeur]

Less friction thus the clutch is more prone to slip. Go here for a good article on the subject: http://www.eric-gorr.com/techarticles/mototech_june_1999.htm

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SHN

99'YZ-400 (Mine)

00' TT-R 125 (Hers)

91' KX-125 (Son #1)

93' CR-80 (Just sold it. Looking for another TTR125 for Son #2)

99' PW-80 (Son #3)

[teamtoxic]

<font color="navy">I came home from school yesturday, the things I ordered were on the porch. I went out in the barn, ripped out the old stuff and took the gear off the backside of the basket.

Has anyone had the springs between the basket and gear gouge their basket? Mine had some decent sized gouges in it.

Anyhow, I put the new basket in there. Soaked the friction plates in Mobil 1 15W-50(thanks anmerdeur) and put those in there. Put the bike together and filled it up w/ Mobil 1 15W-50. Started it up, let it warm up and took off. Engagement is even better than it was after I cleaned up the old basket. Very smooth. "I can't believe it's not butter" smooth. Real nice.

I hope this combined with using the 15W-50 will solve my problems. Looks promising as of now.

Originally when I bought my bike I WAS using the Mobil 15W-50 but somehow, I ended up with a case of Mobil 1 10W-30 the last few times and according to the manual, that should have worked fine. So the last 8 months or so I was using the 10W-30, that may have been my problem.

I wasn't expecting to have my new clutch for the weekend, I'll feel much more confident with the new stuff.

Thank you all for dealing with me the last few days. ?

Special thanks to enmerdeur for pointing out the oil situation!

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~~~~~YaMaHaFoUrTwOsIx~~~~~

[This message has been edited by teamtoxic (edited 05-23-2001).]

[enmerdeur]

? LET'R RIP!!!!!!!!!!!!!!!!!!!!!!

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SHN

99'YZ-400 (Mine)

00' TT-R 125 (Hers)

91' KX-125 (Son #1)

93' CR-80 (Just sold it. Looking for another TTR125 for Son #2)

99' PW-80 (Son #3)

[YZmann]

Teamtoxic, you are aware that your plates blued because the ridges in the basket caused the plates to hang slightly during reengagement under load. In the early stages this is in perceptible, as the clutch slips during re-engagement, but gets more pronounced as the indentations in the basket become more severe. This is NOT caused by the use of a synthetic based lubricant. If a lubricant were causing a slippage problem you would see it under high loads with clutch engaged. Any engineer designing a clutch pack (automotive (e.g. automatic trans has multiple packs)/motorcycle/etc) has to look at the amount of mass and area restraints he/she is dealing with. Thinner plates allow for more plates in a given mass/area, but the contact area against the basket/hub is smaller resulting in a much higher psi pressure point on the basket/hub (plus a lower thermal capacity). A good lubricant will also allow for smoother clutch operation under load by allowing the plates to slide on the basket/hub freely during engagement/disengagement.

Typical clutch durability testing would simulate the environment the clutch is in (including temperature of oil), cycling it X number of times. Then measuring the amount of torque required to break the clutch free. This would be continued repeatedly for the life of the test. The proper way to (in service) to check the clutch would be run the engine, cycle the clutch, stop engine and pull the clutch cover. Have a spider assembly with a nut welded in the center grasp the inner hub. You would then lock the rear brake and use a torque wrench to measure the torque required to break the clutch free. Remember too, that the clutch fiber plates are designed to overcome an oil film on the metal plates. Any proper clutch design has more than ample capacity (typically 100% more than required) and can handle a synthetic (we're not talking about any moly type additives which would contaminate the fiber plates). The 426's clutch is NOT bathed in oil and actually runs drier than most current 2-stroke clutches, this means it has a much higher frictional coefficient.

I really get sick of "expert opinions" with not an ounce of scientific testing to back it up. My industry gets sued enough with thorough detailed testing done (its bad enough doing a test then, when reviewing data, realize you forgot to take something into account and have to start over). I can't imagine what would happen if we "played it by opinion" (lawyer field day). And that is also why a manufacturer will not recommend a product unless they have tested it (legal paranoia). Why walk out on a limb if you know something else is acceptable. Synthetics are being used/looked at as OEM in engines, transmissions and differentials (including limited slip).

If your interested the approximate power that the clutch can transmit is:

Hp = (frictional coefficient (~.3 in our case)*(number surfaces)*(mean radius of plate)*(spring pressure force)* rpm/63,000

Note that this is a linear equation.