Clutch diaphram spring

[PETDOC]

My '04 1150 GS with 31,000 miles just had the clutch diaphram spring rotate and necessitate a major repair ( clutch job). I'm just curious if anyone else has experienced this problem?

[Stan Walker]

My '04 1150 GS with 31,000 miles just had the clutch diaphram spring rotate and necessitate a major repair

 

If you are quoting them correctly, then I would be very suspicious of their understanding of how the clutch works. The diaphram spring has no prdetermined alignment and is sandwiched between two parts that are bolted together. They all rotate together as a single unit. It's only other point of contact with the outside world is the push rod that actuates the clutch. The other end of that rod is inserted into the clutch slave cylinder and the throw-out bearing in there allows the rod to spin with the diaphram spring.

 

Now if that bearing fails and prevents the rod from spinning you might have a big problem, but no way would I describe it as the "diaphram spring rotated".

 

Stan

[Ken H.]

My '04 1150 GS with 31,000 miles just had the clutch diaphram spring rotate and necessitate a major repair

 

If you are quoting them correctly, then I would be very suspicious of their understanding of how the clutch works. The diaphram spring has no prdetermined alignment and is sandwiched between two parts that are bolted together. They all rotate together as a single unit. It's only other point of contact with the outside world is the push rod that actuates the clutch. The other end of that rod is inserted into the clutch slave cylinder and the throw-out bearing in there allows the rod to spin with the diaphram spring.

 

Now if that bearing fails and prevents the rod from spinning you might have a big problem, but no way would I describe it as the "diaphram spring rotated".

 

Stan

+1

 

Somethings missing here.

[PETDOC]

I posted a description of the noise coming from my clutch on ADVRIDER (http://www.advrider.com/forums/showthread.php?t=248520) and the first responder nailed it as a rotation of the inner portion of the clutch diaphram spring. I and a friend took my bike apart and I have the defective diaphram spring in my hand. The central disc is held in place by 3 small fingers and 3 small metal protrusions that interdigitate with the larger fingers in the larger outer disc. On my diaphram spring one of the fingers on the center disc has moved over and the metal protrusion is now pushing one of the larger outer metal fingers inward. The lack of familiarity with this problem gives me some piece of mind that it is very uncommon and I won't be tearing into my clutch with great frequency.

[PETDOC]

As an after thought. I don't have anywhere to park a photo, but if someone else does I'd be happy to email them a couple of pictures of the defective clutch diaphram spring.

[Stan Walker]

I would be looking for a cause. In my opinion this doesn't just happen by itself. Defective parts are always possible.

 

If no one else offers to host your pictures I'll do it, but can't do so until this evening after work.

 

Sending private mail with email address.

 

Stan

[Stan Walker]

Pictures of the clutch diaphrom spring.

 

#1

 

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If I did this right, the original gallery can be found at

my smugmug

 

Anyone to offer up a theory on how or when this can happen?

 

Stan

[T__]

Stan, it’s difficult to voice an opinion or theory without seeing the other clutch parts (especially the pressure plate, pressure plate straps & a good look at the diaphragm spring contact area on the pressure plate).. If something is amiss there it could lead to the diaphragm spring trying to carry some driving torque.. Need to see all the parts to really understand what happened.. And even then seeing pictures is not the same as actually handling the parts..

 

Twisty

[Ken H.]

Humm, I've never seen one do that. There normally is no rotational force between the center hub and the spring plate. A stuck clutch push rod and throw out bearing would be one (abet weak) theory, but the OP didn't mention anything about that. A really weak spring plate would be another, but they don't seem to show any signs of heat damage or anything in the photos. I just don't know. It will be interesting to hear anyone else's theory.

[PETDOC]

Some additional details from the unfortunate source of the slipped diaphragm spring. My bike is an '04 1150 GS, purchased new and maintained with extreme loving care by me. All scheduled maintenance done by the book or more often. It has been flawless in operation for nearly 31,000 miles; recently finished a 9,000 mile trip to Seattle and back to Knoxville; for 2,000 miles my wife joined me. After returning I parked my motorcycle for 2 weeks as I had to go back to work and catch up. One Sunday I took it for short drive to get engine up to operating temp prior to changing oil in engine, transmission and final drive. When back on my driveway returning to garage I could hear an intermittent screeching noise that was not synchronized with the engine rpms and persisted when the bike was parked in neutral. The noise ceased whenever the clutch was pulled in. I posted my observations on ADVRIDER (see link in earlier post) and the first person to respond told me precisely what had happened. Despite posts here and on the MOA site, no one else seems to have experienced this particular failure. I rode my bike 20 miles to a friend's house who is helping me with the repair, and the bike worked fine except for the intermittent screeching. (Mind you I didn't try to do any wheelies.) I decided to replace pressure plate and push rod, but neither seem to have any obvious defects. The clutch disc appears to have at least 50% of original thickness and the splines look like they just came from the factory. I'm waiting for parts and hoping I can ID factory marks on housing cover and clutch housing or I may be forced to put old pressure plate back in, which I dutifully marked prior to dissassembling clutch apparatus.

[jlupton]

Not a definite answer for sure, especially with the clutch pictures. I had a sudden screeching sound start on my 2002 RT with 24,000 miles. The advise I got was the throwout bearing inside of the slave cylinder.

 

Once I got the slave cylinder out I found that what used to be a small roller / thrust bearing had completely disintegrated, hardly any balls fell out and those that did were very damaged.

 

I replaced the slave cylinder, gasket, stupid felt thingy, cleaned the junk brake fluid out of the clutch master cylinder, put in a speedbleeder and flushed the system a number of times. So far, so good.

 

The slave cylinder was the hardest part to get, seemed that it was suddenly on back order everywhere. $121.00 or so from MAXBMW (???)

 

R+R of the slave cylinder is tight, but pulling the rear wheel and the bottom shock bolt allowed me to sneak my hands and tools in.

[PETDOC]

Not a definite answer for sure, especially with the clutch pictures. I had a sudden screeching sound start on my 2002 RT with 24,000 miles. The advise I got was the throwout bearing inside of the slave cylinder.

Interesting prospect. Did the screeching noise stop when you pulled the clutch lever in? Mind did.

[Stan Walker]

Well I've eyeballed the pictures, I've held a brand new diaphragm spring in my hands, I played with the whole clutch setup off my '96 RT (similar in concept), and I've stared endlessly at the 3 different repair manuals I have.

 

So here is my thoughts, painful as they are.

 

If you look at the pictures you will notice that it's not so much that the center part of the spring rotated, as it is pushed off center. To me this is the big clue.

 

Assuming that the bolts that hold this assembly together were all present and reasonably tight, there is no way this can happen in my opinion. The outer part of the spring sits in a recess in the clutch housing and therefore cannot move off center. The inner part of the clutch spring has the release push rod inserted through it's center hole and I believe the push rod projects far enough to enter the center hole in the rear end of the crankshaft. If true this would prevent the center section of the diaphragm spring from moving off center as well.

 

Yet, the pictures clearly show the two parts are no longer aligned on the same center. I believe that this occurred upon removal of the transmission and was caused by not removing the push rod beforehand and by allowing the transmission to tilt and / or to apply weight to the push rod while the transmission was being removed. This in turn caused the shift of the center portion of the spring. Of course I was not there and as Twisty points out I haven't handled or even viewed in a photograph all the parts. So it's just my theory.

 

So what caused the original noise? As has been pointed out, a failed slave cylinder pilot bearing can make a noise similar to that described. That would be the first thing I would check. It's a known weak spot in the 1150's. And for sure I would check and double check that the push rod wasn't bent or damaged before reusing it. Rolling it on a known flat surface comes to mind.

 

So that's my 2 cents for today.

 

Stan

[PETDOC]

Stan,

Thank you and others for your thoughtful insights on my bike's problem. Probably the only way I can test your hypothesis is to reassemble my bike without replacing the clutch slave cylinder and I'm not sure I will do that as I'd like to get this thing off my friend's rack and back on the road. All I can add is there were 2 of us carefully removing the rear drive and transmission, and the entire assembly was raised to near waist level by a bike rack so we were pretty much backing straight out. The pushrod looked pretty straight, but I did not roll it on a flat surface (but will). By using a flat bladed screw driver I was able to lift the errant fingers on the core of the diaphram spring and snap the center back in place, but I'm still replacing it and the pushrod.

I have had additional communications with the individual (BMW-K) who replied to my original request for help on ADVRIDER and asked him for his thoughts on the possible culpability of the slave cylinder and his reply was.....

"In my case the diaphram springs was 100% the culprit. It's actually happened to me twice, once on my old K100RS. The screaching sound ONLY happened when the clutch was dis-engaged (handle pulled in), right?

So what was happening is that when the clutch is pulled in the clutch plate itself is now free to spin around - only it can't spin freely because the spring is now on a very slight angle (caused by the center plate now not being centered). So the noise is coming from the loose finger vibrating and the the pressured off-kilter spinning of the plate. The noise to me almost sounded kinda like a steel trashcan lid with a half dozen forks in it being dragged across the asphalt road in front of my house - shang-shang-shang-shang... and I could also feel a grinding like feeling through the footpegs"

 

If I can identify an defects in my slave cylinder I'll post the results.

Thanks again for all comments.

[SHIMHEAD]

Here is my take on this. Careful inspection of the pictures tells a story....notice the "witness marks", the rusty areas of contact between the center plate and the diaphram spring fingers...imagine the areas of contact in the alignment necessary to have created them...apparently they were in correct alignment during operation! The rusty appearance is normal for this type of metal in this application. You might try this to help isolate the noise further...chuck the pushrod in a drill, spin it up as fast as you can, any bending should be apparent....then try using the drill to press the pushrod into the slave cylinder in a simulated operation of pulling the hand lever (observe the normal direction of rotation of the crankshaft)...if the noise occurs, then the release bearing is highly suspect. This viewpoint comes from 26 years of automotive technician experience and a great need to simplify the diagnosis to the "real" problem. Be logical, think clearly about the way the system operates, and NAIL IT DOWN!

 

 

David F.

06 R12RT

[PETDOC]

Here is my take on this. Careful inspection of the pictures tells a story....notice the "witness marks", the rusty areas of contact between the center plate and the diaphram spring fingers...imagine the areas of contact in the alignment necessary to have created them...apparently they were in correct alignment during operation!

Dave,

I agree up to a point. The bike worked flawlessly for 30,700 miles and only started to make the screeching noise during the last 25 miles. Twenty of which were in route to friend's lift so I could repair problem. So whatever happened became apparent suddenly. Question remains did the diaphragm sping core shift due to never to be explained reasons or was something like a bound up push rod to blame. Stan's theory that the core only shifted during removal of the transmission is plausable; however, I do not believe that to be the case due to the care that was exercised during removal. If after replacement there is no obvious damage to the slave cylinder I most certainly will use your suggested technique to see if I can recreate the screeching.

All parts should be here next week and no matter what I find I will report back. My greatest hope is I will post exactly what happened and the bike works great. Next choice is bike works great but there is no definitive answer, and my secret fear is everything has been replaced and it still makes the noise. Again I appreciate everyone's thoughts.

[SHIMHEAD]

I would like to add a couple more observations. I also noticed some other marks on the parts where they were misaligned...notice the color of those marks...I'd bet you could recreate those types of marks by sliding the parts across each other with some pressure (similar to marking a part with a scribing instrument)...these reek of movement between the parts during disassembly. Consider the distance the parts were off from the correct location...that distance is rather small, and it is very likely that even with two people removing the transmission that at least that distance was covered as the transmission came off the alignment dowels. Also, careful inspection of the friction surfaces of the flywheel/disc/pressure plate should give some clues as to the operating condition of those parts. Keep in mind that these parts are in close "spring loaded" contact when the clutch is engaged, enough pressure to transmit ALL the torque of the engine. The only other area I'd be curious about is the center hub of the disc, being sure nothing is damaged/worn/loose. If indeed the center piece of the diaphram spring were out of position during operation, then the posibility exists for the pushrod to have contacted the inside surface of the input shaft, thus leaving marks on those parts as well, since the pushrod would have been rotating in an orbit and not on a center. I'm betting on a release bearing issue with the present information. Strongly suggest using some modified bolts on reassembly as alignment aids and installing the clutch pushrod AFTER the trans is bolted up! Keep us posted!

 

 

David F.

06 R12RT

[PETDOC]

Well for the rest of the story....... The clutch slave cylinder was bad. After I removed it the bearing had excessive play and with minor manipulation little ball bearings came running out. Everything is back together again. The bike has a new clutch diaphram spring, pressure plate, disc, pushrod and slave cylinder, and runs like new. I took the old pushrod and rolled it on the flat surface of my table saw and could detect no bending at all; it appeared perfectly straight. I can't say Stan's theory of an iatrogenic dislocation of the center portion of the diaphragm spring during transmission removal was impossible; however,having been the one who removed the transmission I will say I'd swear on whatever anyone holds sacred that it did not happen that way. Proof may eventually come when/if a future poster has a similar problem. For now I like Ken's theory

Humm, I've never seen one do that. There normally is no rotational force between the center hub and the spring plate. A stuck clutch push rod and throw out bearing would be one (abet weak) theory, but the OP didn't mention anything about that.

Again thanks to all for your input and a special thank you to my friend Kreis for helping me do this royal PITA job.

PS. The engineer responsible for the design and positioning of the airbox in the 1150s should be fired!

[Stan Walker]

Darn, I get no respect around here..........

 

I mentioned throwout bearing and slave cylinder in the second post of the thread, but KEN gets the credit......

 

Hey, we're just glad you got it all back together and running again. Having done this twice I agree the airbox is a real pain in the a$$. You deserve a gold star!

 

Stan

[PETDOC]

Darn, I get no respect around here..........

I mentioned throwout bearing and slave cylinder in the second post of the thread, but KEN gets the credit......

Stan

Stan... sorry for the omission, kudos to you as well. Thanks for the posting of torque specs on slave cylinder union bolts in other thread I obviously missed it in my shop manual--torqued mine a little too tight but I'll leave it alone as I don't have any more crush washers.

 

A warning to other 1150 owners... when I ordered the clutch slave cylinder from the BMW dealer he sarcastically said "a clutch slave cylinder, what a big surprise". I asked him if they had a high failure rate and he replied affirmatively.

 

Stan one last question--let's assume the slave cylinder did bind the push rod which subsequently caused the core of the diaphragm spring to rotate as seen in photos. Knowing that I was able to reposition the core and the diaphragm spring looked normal, if I had fixed the slave cylinder and never opened up the clutch assembly do you think the the diaphragm spring core would have automatically repositioned itself after several clutch engagements?

[Stan Walker]

let's assume the slave cylinder did bind the push rod which subsequently caused the core of the diaphragm spring to rotate as seen in photos. Knowing that I was able to reposition the core and the diaphragm spring looked normal, if I had fixed the slave cylinder and never opened up the clutch assembly do you think the the diaphragm spring core would have automatically repositioned itself after several clutch engagements?

 

Given that assumption,,,,, no.

 

But, Your spring wasn't just rotated, it was off center, so I have some problems with the assumption.

 

Stan

[NonComp]

A warning to other 1150 owners... when I ordered the clutch slave cylinder from the BMW dealer he sarcastically said "a clutch slave cylinder, what a big surprise". I asked him if they had a high failure rate and he replied affirmatively.

I'm beginning to like my 'new' r1100r more and more -- cable actuated clutch with no bearings for one thing.

[Stan Walker]

with no bearings for one thing

 

Well, I won't be the one to tell you otherwise, so don't read past this point.

 

There is a throwout bearing in the 1100's too. It does seem to be a lower failure rate item. Still, I've got 91 K miles on my '02 and I am still on the original slave cylinder and bearing. I did check it and regrease it at 70,000 when I did my spline lube.

 

Stan

[NonComp]

OK, maybe this is a stupid question, but where's the bearing? Mine has a piston with what looks like a hardened surface that bears directly on the end of the pushrod. No bearing per se, but two surfaces that meet, for sure.

 

Edit: Doh! The answer's that the bearing is in the arm, or course. Sorry.

[Ken H.]

I mentioned throwout bearing and slave cylinder in the second post of the thread, but KEN gets the credit......

Hey Stan, I'll PM you my credit. Don't spend it all in one place!

[Stan Walker]

Edit: Doh! The answer's that the bearing is in the arm, or course. Sorry.

 

Don't be sorry.

 

The absence of anyone with real data points out how seldom the throwout bearing used on the R1100 fails.

 

I think (but I confess to never taking one apart) that the bearing is in the "piston" assembly. The darn thing has a list price over $50. Surely you get something cool (like a bearing) for that!!!

 

Stan

[NonComp]

When I think of throwout bearings, I think of automotive or truck applications where the bearing might be located in the center of the clutch assembly. Maybe that's an obsolete concept now.

[Ken H.]

When I think of throwout bearings, I think of automotive or truck applications where the bearing might be located in the center of the clutch assembly. Maybe that's an obsolete concept now.

Don't feel too bad, the BMW bike design of putting the 'throw out bearing' at the rear of the tranny and actuating the clutch through the center of a hollow transmission input shaft, while not unique is definitely unusual.

[SWB]

think (but I confess to never taking one apart) that the bearing is in the "piston" assembly. The darn thing has a list price over $50. Surely you get something cool (like a bearing) for that!!!

 

Mine was replaced when Tom Cutter went through the transmission. He said it was toast, and probably went prematurely due to a mis-adjusted clutch. (Of course, my bike probably had 20 different riders and trainees, so that might have had something to do with it too.)

 

57K miles at replacement.

[RFW]

My '04 1150 GS with 31,000 miles just had the clutch diaphram spring rotate and necessitate a major repair

 

If you are quoting them correctly, then I would be very suspicious of their understanding of how the clutch works. The diaphram spring has no prdetermined alignment and is sandwiched between two parts that are bolted together. They all rotate together as a single unit. It's only other point of contact with the outside world is the push rod that actuates the clutch. The other end of that rod is inserted into the clutch slave cylinder and the throw-out bearing in there allows the rod to spin with the diaphram spring.

 

Now if that bearing fails and prevents the rod from spinning you might have a big problem, but no way would I describe it as the "diaphram spring rotated".

 

Stan

EXACTLY! Someone is not clear on the basic concepts here!