Clutch plates keep breaking

[mxstar1]

I keep breaking my clutch plates, and i cant figure out why here are all the details, maybe someone can help; 2005 crf450r

So a few races ago my bike starts making this ticking noise, It runs fine, its just ticking from the lower end when i pull in the clutch. I pull out the clutch and one plate falls apart in my hand. I buy another oem clutch kit, install it and two races later, I lose my tranny, I pull apart the engine, and two clutch plates are destroyed and in pieces, also, one of the gears in the tranny on the countershaft spindle is jacked up and wobbling around, causing my bike to not go in gear. No big deal, fixed that, but why are my plates breaking!! There is no play whatsoever on the shaft that holds the basket, I bought a new needle bearing and sleeve for the basket the last time i replaced the clutch. however if you look at the basket there is a rub mark all the way around it where it meets the edge of the outer right case. its catching the plates and breaking them.....but why, what is worn out. Like i said there is no play up and down on the shaft. The basket has a little free play but no more than my buddies bike. it is definately rubbing and its rubbing on the bottom of the outer right case. I cant get it to touch when its just sitting there, but when the motor runs, its definatley touching.

Any ideas???

[Shawn_Mc]

You said new bearing and collar...I assume youre talking about #21 and #3?

If Bearing #36 were bad, it could allow the kind of play you're talking about under a load when the engine pushes on that part of the trans via the primary drive.

If Bearing #35 were bad, it could do the same thing, but you wouldn't be able to tell by hand.

[mxstar1]

yes, #21, and #3 were replaced on my first attempt. when the tranny blew, gear #10 was destroyed and so was the shaft #2. I replaced them, I just put all new bearings in the case 1 year ago when i rebuilt the motor, and i checked all the bearings inside the case and they seem to be smooth, no play. But i could replace them.

So you think that if the countershaft bearings are bad it could make the primary drive wobble?

How about the big washer on the basket, i seen where someone said they wear out and make the basket wobble.

Im also gonna tear down the basket and see if the cushions are ok tonight.

Could that be it at all?

[MELK-MAN]

cusions could be MISSING and it won't cause the plates to break. I have had my cusions totally disintigrate when my bike got a bit hot (leaking wp seal). You will have a "clank-clank" noise when you get on-off gas, but the basket, plates and pressure plate will stay in line as long as the inner boss nut is secure.

[thekidd77]

I just had mine apart

I noticed when pushing the clutch basket in it seemed all the way in but needed rotated until a certain spot and then it slid into the case even further.

I assume you mean the discs are breaking the ones with the brake material on them not the smooth plates. Mine had a broken disc, the impression i got is that every time the clutch engages all the disc tabs hit the basket and all the spacer plates hit the inner gear, over time this notches the basket fingers and the inner gear. the discs and plates are supposed to slide in and out along the basket fingers freely but I think the tabs on the discs got caught up in the worn basket finger groves and snapped the disc, i just filed the grooves out of the basket fingers and I have a new set of discs and plates coming.

[CRFPOOR]

My 09 450 was breaking them every moto and it was the cushions that fixed my problem.

[MELK-MAN]

My 09 450 was breaking them every moto and it was the cushions that fixed my problem.

(as posted earlier) my plates were still like new after an hour of getting back to my vehicle from the woods with NO cushions.. lots of "clank-clank" when on-off gas, but if everything is in line and assembled you wouldn't have plates break even without ANY cushions.. if they were in the rear wheel hub like roadrace bikes, you wouldn't need them in the basket at all, the gear could be bolted directly to the basket. The basket cushions only provide "cush" from on-off gas forces, nothing to do with side to side play. In the event a spindle bearing is worn or something else is out of spec they won't keep the basket in line..

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[nicky-san]

Exploded 3 friction plates on my 2010 a month ago, replaced the clutch set and found one mre friction plate exploded last week-end - tell tale sign was lot of shiny material during oil change......

Had same issue once with my 2007 and never re-occured, not the cushions for sure

I have Pro-Circuit HD springs on my 2010, I suspect the breakage is from brutal engagement going out of berms in deep loam combined with jerky EFI at low RPM casuing increased stress on the basket IMO

Planning on putting Rekluse core 2.0 to calm down my clutch happy hand and see if this goes away.

[Rocksalt]

you wouldn't have plates break even without ANY cushions..

The point of contact of the friction plates is the outer basket. This is the point of power transmission. If the power is applied gradually there are less shock waves generated at that point. Every time you back off on the throttle and re-apply it acts like a hammer. It would seem highly possible to break plates doing this. A grooved basket could also cause the tangs to break.

[MELK-MAN]

The point of contact of the friction plates is the outer basket. This is the point of power transmission. If the power is applied gradually there are less shock waves generated at that point. Every time you back off on the throttle and re-apply it acts like a hammer. It would seem highly possible to break plates doing this. A grooved basket could also cause the tangs to break.

grooved fingers on basket would be more likely, but still NOT likely the issue. Do you see how many riders post about "fingers worn, should i replace my basket??" and NO broken plates. It is a rare occurance. Lots of the force is just lost to the rear tire in the dirt too. Think about it. No cushions is not likely causing the problem, See above photo!! been there, done that.. for over an HOUR in the woods. Clutch fibers were still looking like new and over 3mm.

I mean come on.. his (original poster) cushions are NOT missing, or even look anything like the pic i posted. Even if the little tab is broke that holds the two halves of the cusion together, it won't matter! all that does is make life easier putting them in so you get the thick half on the drive side.

Stuff not lining up, or the basket is wobeling a bunch due to worn sleeve bearing, bad CLUTCH SPRINGS that allow the clutch pack to slip and generate excessive heat, who knows.

[Rocksalt]

https://www.thumpertalk.com/forum/showthread.php?t=945554&page=2

What is good for you may not be good for someone else. Depending on how a rider rides may change the course of the outcome.

Einstein was able to make a bridge collapse by using frequency as a tool. The resonance he created in the structure caused it to break apart. If you make just the right frequency you can break almost anything.

Without the cushions you are transmitting a force many times more than it was designed to handle. If you had no cushions and the ring gear were permanently fixed to the basket you would wear down the basket and fingers many many times faster.

Do you think the cushions were installed to help power delivery or save the mechanical parts from shock loading?

[MELK-MAN]

https://www.thumpertalk.com/forum/showthread.php?t=945554&page=2

What is good for you may not be good for someone else. Depending on how a rider rides may change the course of the outcome.

Einstein was able to make a bridge collapse by using frequency as a tool. The resonance he created in the structure caused it to break apart. If you make just the right frequency you can break almost anything.

Without the cushions you are transmitting a force many times more than it was designed to handle. If you had no cushions and the ring gear were permanently fixed to the basket you would wear down the basket and fingers many many times faster.

Do you think the cushions were installed to help power delivery or save the mechanical parts from shock loading?

Lets just leave Einstein out of the discussion till the oP tells us if his cusions are there or not ! ?

[Shawn_Mc]

Do you think the cushions were installed to help power delivery or save the mechanical parts from shock loading?

Definitely against shock loading. The transmission gears wouldnt last a single moto without the cushions. I learned this the hard way about 35 years ago. I built an SL125 engine up to 198cc with a ported head and Powrol Cam and all kinds of goodies and that thing made really good power for what it was. Put it in a 1977 RM125 chassis. The stock RM rear wheel didnt have a cushion drive. The SL engine didnt have any cushion in it either. The end result after a single ride was a destroyed first gear...so I fixed it...and it did it again. So I fixed it again...and it did it again...Not until I laced the Honda hub into the RM rear rim and made all the adapters I needed to run the Honda Wheel in the RM swing arm did it stop blasting the trans out in ultra short order.

And for what its worth...I never blew up the clutch on that bike. So it aint the cushions. Something is wrong with the drive gear. the basket is wobbling somehow and breaking the plates.

[nicky-san]

Shawn, I am candidely looking foward to be educated before I throw good money after bad,

As stated above, I was planning on replacing the ass'y with Rekluse core EXP 2.0 without a solid root cause analysis to reduce cluch use and hopefully solve the issue ( I got my bike new last April and have 46 hrs-only have PC HD springs and Yosh full line on the motor)

Can you explain how a wobbling basket ( that carries the friction plates that also wobble at the same frequency) can induce plate breakage ?

tks, Nicolas

[nicky-san]

Also, would an Hinson basket , 6 springs, be better solution as there are 6 pressure point instead of 4 distributing a lower localized pressure on the friction plates?

[MELK-MAN]

Shawn, I am candidely looking foward to be educated before I throw good money after bad,

As stated above, I was planning on replacing the ass'y with Rekluse core EXP 2.0 without a solid root cause analysis to reduce cluch use and hopefully solve the issue ( I got my bike new last April and have 46 hrs-only have PC HD springs and Yosh full line on the motor)

Can you explain how a wobbling basket ( that carries the friction plates that also wobble at the same frequency) can induce plate breakage ?

tks, Nicolas

.. (not to speak for Shawn).. but the clutch pack is NOT held at same "frequency". The basket rides on a double roller needle bearing on the shaft. The inner clutch boss slides onto the splines at the end of teh shaft. Then, the pressure plate rides on a bearing on the end of the lifter rod. If the needle bearing is bad, the basket coudl wobble while the inner clutch boss (that the metal plates ride on) remain stable! Then as Shawn indicated there is a drive gear on the end of the crank, that rotates the large drive gear attached to the back of the outer clutch basket. LOTS of things could be going on..

[nicky-san]

OK thanks Melk-man,

I suppose I need to do due dilignece and disassmble the whole clutch to find out argh...

[Rocksalt]

And for what its worth...I never blew up the clutch on that bike. So it aint the cushions. Something is wrong with the drive gear. the basket is wobbling somehow and breaking the plates.

I don't want to beat this dead horse but I feel compelled to respond.

Believe it or not your experience solidifies my hypothesis. Surely broken transmission gears, in your case, could have been a broken clutch pak. The gears were the weak point in that bike. Have you heard of a operator breaking his transmission because his cushions were worn out on a CRF450R?

I am not saying this is the problem with the posters clutch but I am inclined to believe this more than a bad bearing on the clutch shaft causing a misalignment. If anything a bad bearing could cause a resonance that does damage the clutches.

If the basket were to come in contact with the engine cases could it break the tangs on the clutches? They do not protrude from the basket. Any marks seen on the basket most likely were from the broken pieces.

Another possibility is some type of gear lockup which would suddenly cause the basket to stop.

[thekidd77]

Just reread the OP and he says he is certain his basket is rubbing on the case. If that is true he definitely has some kind of issue with how the basket is sitting on the needle bearing. I was more thinking about my own bike that I am waiting for the clutch kit to arrive for. Mine had a single broken fiber disk about a two inch chunk broken off. All the discs looked in good condition no burn look or worn out. My basket has no wobble or clearance issues, just some decent grooves on the basket fingers, and very very minor grooves on the inner hub. The springs and dics all measured above the minimum tolerances in the manual.

I assumed filing the fingers and a new set of fibers, plates, and springs would fix it up brand new. But from what you are all saying there must be some other reason that fiber disc broke....got me worried now LOL

I bought the bike used for $2500 in Canada, so a smoking deal on an 05, so expected to do some repairs.

[MELK-MAN]

Just reread the OP and he says he is certain his basket is rubbing on the case. If that is true he definitely has some kind of issue with how the basket is sitting on the needle bearing. I was more thinking about my own bike that I am waiting for the clutch kit to arrive for. Mine had a single broken fiber disk about a two inch chunk broken off. All the discs looked in good condition no burn look or worn out. My basket has no wobble or clearance issues, just some decent grooves on the basket fingers, and very very minor grooves on the inner hub. The springs and dics all measured above the minimum tolerances in the manual.

I assumed filing the fingers and a new set of fibers, plates, and springs would fix it up brand new. But from what you are all saying there must be some other reason that fiber disc broke....got me worried now LOL

I bought the bike used for $2500 in Canada, so a smoking deal on an 05, so expected to do some repairs.

a broken disk or 2 after many many hours on a clutch is not unusual. Most racers/serious riders just don't let it get to that point. If lucky, the fiber breaks in a large enough piece it just remains in line with the remainder of the fiber plate, and no real harm is done.

you will find MANY threads discussing filing the fingers of the basket. It will get you by for awhile, but you have now increased the tolerance of the fiber plates finger to the basket finger.. it now will SLAM with a bit more force, speeding up the time in which your basket fingers will knotch. Be looking for a new basket fairly soon, but pulling the outer cover off takes very little time to you can inpsect it. The fiber plate fingers wear too! Don't just assume because the fiber is over 2.85mm that all is well.. ?