Checking for spline wear 1999 R1100S

gsaddict · Dec 22, 2013

nrpetersen said:
The reason shaft wear is tapered is that the flex plate is near that end of the spline hub, concentrating and reacting any radial load there.

There is no resonance related problem here. I designed several high speed spinning torsional vibration test stands for the auto industry before retirement.

No disrespect here but you are aware that the flex plate is centered past the end of the input shaft?
The engine turns clockwise viewed from the front.
How do you explain the wear on the left side of the shaft spline further down.
Why are the hub splines typically worn evenly along their length?

Unless......this wear happens on deceleration? I can't see that.

.

nrpetersen · Dec 22, 2013

GSAddict said:
No disrespect here but you are aware that the flex plate is centered past the end of the input shaft?
.............

Definitely questioning this is not disrespectful. This would be a show stopper for me!!!!! - I gotta find a picture....Have you got one that shows it? In one of the forums I saw one that was a new disk placed on the transmission shaft but from some other pictures I concluded it was placed on the shaft backwards for the photo-op. My Clymers isn't clear. Frankly I've only seen the inside of two R1100s & that was a couple of years ago.

This would be a lot of words to eat..........

gsaddict · Dec 22, 2013

nrpetersen said:
Definitely questioning this is not disrespectful. This would be a show stopper for me!!!!! - I gotta find a picture....Have you got one that shows it? In one of the forums I saw one that was a new disk placed on the transmission shaft but from some other pictures I concluded it was placed on the shaft backwards for the photo-op. My Clymers isn't clear. Frankly I've only seen the inside of two R1100s & that was a couple of years ago.

This would be a lot of words to eat..........

That is why I posted the picture. I have many pictures from the bikes I repaired.
What other ones would you like me to post?

Here is a good example of a catastrophic failure. (from the other side of my last post)
note the hub orientation

nrpetersen · Dec 22, 2013

I found that you are right and I was wrong. See posts around #69 at

http://forums.bmwmoa.org/showthread...put-shaft-spline-ÔÇô-need-advice-please/page5

which shows a clutch still mounted to the flywheel. :hide

Based on that I now can't explain why the principle shaft wear is nearest the transmission (unless it is local lack-of-comparative hardness?). I am still sure however that initial spline wear is caused by radial misalignment (yeah - I know - only fools are sure).

On the Sach's axial run out test post by Roger RT, where they looked for 0.5 mm run out at the disk OD, given a flex plate between the hub and the friction disk, how many ounces of force would be needed to deflect the flex plate that 1/2 mm? The picture they show is a more rigid hub/damper combination. That's why I don't think clutch disk run out is that critical for our situation.

(2-10-14 addition - The reason the shaft spline wear is curved, is most certainly that the end of the shaft is so hard that most of the initial hub wear is at the that engine side. The hub wears uniformly and then in a conjugal pattern along its length until finally there is only a very small amount of hub teeth holding everything - and then it strips out.)

gsaddict · Dec 22, 2013

nrpetersen said:
I found that you are right and I was wrong. See posts around #69 at

http://forums.bmwmoa.org/showthread...put-shaft-spline-ÔÇô-need-advice-please/page5

which shows a clutch still mounted to the flywheel.

Based on that I now can't explain why the principle shaft wear is nearest the transmission (unless it is local lack-of-comparative hardness?). I am still sure however that initial spline wear is caused by radial misalignment (yeah - I know - only fools are sure).

On the Sach's axial run out test post by Roger RT, where they looked for 0.5 mm run out at the disk OD, given a flex plate between the hub and the friction disk, how many ounces of force would be needed to deflect the flex plate that 1/2 mm? The picture they show is a more rigid hub/damper combination. That's why I don't think clutch disk run out is that critical for our situation.

That is why I found that vibration theory (torsional whip) so interesting.

nrpetersen · Dec 22, 2013

In studying past pictures, there are a series of three (?) flex plates connected to the flywheel around the perimeter of the clutch pack, that I assume are to keep transmit torque while allowing the pressure plate to shift axially slightly. These flex plates could allow the pressure plate to wear non-uniformly. The failure or buckling of one of these perimeter flex plates could load the spline.

What is the difference between the R1100 clutch system and the R1150 system? I've only seen the R1100 system.

nrpetersen · Dec 22, 2013

GSAddict said:
That is why I found that vibration theory (torsional whip) so interesting.

But I can't account for what the mode shape would be. Unless possibly an uneven buckling (for example from a crack?) of the center flex plate (the spider) under high torque.

gsaddict · Dec 22, 2013

nrpetersen said:
In studying past pictures, there are a series of three (?) flex plates connected to the flywheel around the perimeter of the clutch pack, that I assume are to keep transmit torque while allowing the pressure plate to shift axially slightly. These flex plates could allow the pressure plate to wear non-uniformly. The failure or buckling of one of these perimeter flex plates could load the spline.

What is the difference between the R1100 clutch system and the R1150 system? I've only seen the R1100 system.

I have 1150 pictures, but no 1100.
How much they differ I can't say for certain.

Calling Anton to the house phone please.

roger 04 rt · Dec 22, 2013

nrpetersen said:
But I can't account for what the mode shape would be. Unless possibly an uneven buckling (for example from a crack?) of the center flex plate (the spider) under high torque.

I wondered about flexing of the spider plate connecting the hub to the friction disc. It would be interesting to know its deformation at high torque loads.

roger 04 rt · Dec 22, 2013

What does anyone think about the possibility of deformation of the metal web that connects the clutch hub to the friction plate under the following circumstances:

--small centerline offset
--non-flat clutch housing
--full 70 lb.-ft. Torque load

Below is a picture of one rb racing claims to have broken in a turbo. Seems like if you can break one you could bend it at lower loads.

RB

jammess · Dec 23, 2013

I think a clutch disk with an un-sprung hub is not the way to go with the flat twin BMW motor with its associated dry clutch. I came to this conclusion several years ago. You can theorize all day long about the forces at work that destroy input shaft splines but I really think a sprung clutch hub is the cure for the 1150. That and in the mean time avoid 6th gear unless you are traveling at a very high velocity.

gsaddict · Dec 23, 2013

jammess said:
I think a clutch disk with an un-sprung hub is not the way to go with the flat twin BMW motor with its associated dry clutch. I came to this conclusion several years ago. You can theorize all day long about the forces at work that destroy input shaft splines but I really think a sprung clutch hub is the cure for the 1150. That and in the mean time avoid 6th gear unless you are traveling at a very high velocity.

You are aware that the "springs" are on the input shaft inside the transmission right?
The damping is done there.

roger 04 rt · Dec 23, 2013

jammess said:
I think a clutch disk with an un-sprung hub is not the way to go with the flat twin BMW motor with its associated dry clutch. I came to this conclusion several years ago. You can theorize all day long about the forces at work that destroy input shaft splines but I really think a sprung clutch hub is the cure for the 1150. That and in the mean time avoid 6th gear unless you are traveling at a very high velocity.

While it is true that there is more torque on the input shaft in 6th than in 5th, 6th is only about 20% of WOT, and the slower you're going, the lower the torque.

If you really want to grind on the shaft use 1st, 2nd or 3rd at WOT through 4000-7000 rpm. although the engine doesn't seem so loaded, the input shaft is experiencing 100% torque and the shaft teeth are grinding at there highest rate.

R100RTurbo · Dec 23, 2013

Non Flat Clutch Plates

roger 04 rt said:
What does anyone think about the possibility of deformation of the metal web that connects the clutch hub to the friction plate under the following circumstances:

--small centerline offset
--non-flat clutch housing
--full 70 lb.-ft. Torque load

Below is a picture of one rb racing claims to have broken in a turbo. Seems like if you can break one you could bend it at lower loads.

RB

My suspicions lie with your thoughts above Roger, where distortion of both of the metal plates that surround the friction disc is a dark horse contender in the efforts to identifying spline wear. The inner plate (held in orbit by the 3 spring steel fingers) seems to dish away from the friction disk at center. The outer plate (bolts onto flywheel) can be noted as dishing away from the friction disk at its center also. This is not wear but heat warpage I'd suggest resulting from another shortfall to the design excellence of this rather "Rube Goldberg" clutch design. The top plate isn't stiff enough to remain flat being held by its outer bolt circle, the inner plate has a mechanical disadvantage of force against it from the disc spring riding against fulcrum surfaces pretty far out on its diameter. Given the thin, flexible nature of the friction disc "metal web", twisting forces that come to bear against the outer diameter (from being sandwiched between above distorted surfaces) might allow that plate to pucker and nudge the center splined hub into wobble. Add in potential engine to transmission runout, and the short spline engagement and you have a pretty good recipe for short life. Especially if a clutch disc is replaced on its own without a fastidious inspection of all components and replacement there of.
This was discussed in another thread recently, but I wonder how many have put a straight edge on their plates to check during a clutch job (where parts are either tossed, or reused) ??

jammess · Dec 23, 2013

GSAddict said:
You are aware that the "springs" are on the input shaft inside the transmission right?
The damping is done there.

I think the springs on the input shaft are there to protect the drive gear on the shaft from damage caused by pulsing from the engine not to protect the input splines. In other words protection of the input shaft splines from engine power pulses and associated effects of rocking couple should be ahead of the input shaft splines not behind hence the spring loaded clutch disk. Roger, I understand that engine torque is higher at > RPM but because of transmission gearing effects (lower ratio in lower gears) I would think that there is less stress on input shaft splines at higher RPM. Place any manual transmission on your work bench and place it in 1st gear and by hand rotate the input shaft and note how easily it turns then place the tranny in a higher gear and see how easy (or not) it is to turn the input shaft. Try this with a slight load on the trans output to really appreciate the effect of gear ratios.

As kind of a side note I defy anyone to perform smooth shifts consistently with the hydraulic clutch as found on the 1150 motorcycles. the nonexistent flywheel also doesn't help matters.

gsaddict · Dec 23, 2013

jammess;914086 As kind of a side note I defy anyone to perform smooth shifts consistently with the hydraulic clutch as found on the 1150 motorcycles. the nonexistent flywheel also doesn't help matters.[/QUOTE said:
I never have bad shifts, my transmission is butter smooth. Preloading the lever helps but is not mandatory.
I do blip the throttle downshifting, really helps.
No complaints in 254,000 km

gsaddict · Dec 23, 2013

R100RTurbo;914042 This was discussed in another thread recently said:
Most used plates I have seen are not flat from od to id.
I suggest replacement but have reused with no ill effects.

jammess · Dec 23, 2013

GSAddict said:
I never have bad shifts, my transmission is butter smooth. Preloading the lever helps but is not mandatory.
I do blip the throttle downshifting, really helps.
No complaints in 254,000 km

I've been trying to shift smoothly for 45K miles and I just can't seem to manage it unless I ride with the throttle position lever (choke) in the detent. Sometimes I get it right but only sometime. Other two beemers with cable operated clutches no problem. Probably just me and my poor hand/feet co-ordination. :blush

Reminds me of the driving range, sometimes I can do no wrong and other times....... :banghead

23217 · Dec 23, 2013

You are aware that the "springs" are on the input shaft inside the transmission right?
The damping is done there.

I suppose BMW might think of that cheesy little spring as a damper, but in the modern world that would be laughable. Modern day clutches have:

Primary idle damper springs

Secondary idle damper springs

Primary main load springs

Secondary main load springs

Friction washers

Axial cushion segments (single or dual)

These damping springs need to be carefully and correctly calibrated for each engine. Considering that the oilhead has such a long engine stroke and light flywheel, these dampers would be vitally important. Failure to do so will result in premature wear to the input shaft, gear rattle, Gear crashing, premature CV wear, and final drive problem. Damping is need to reduce vibrations, resonance, crank whipping, etc.

As Prashant Kulkarni (engineering manager of Clutch Division at Eaton Corp.) states: " That vibration then moves throughout the entire driveline, through the clutch, the transmission, down the driveshaft and to the axles. If vibration gets to be excessive it can break components like synchronizer pins, transmission and U-joint gears, he explains. ?It can even [impact] gears down in the axle or any other component that is directly in the torque path of the driveline.?

Or, as Schaeffler (clutch mfg) states: "Engine and gearbox tolerances, especially on transmission intake shafts with out pilot bearing, result in a displacement between crankshaft and gearbox. In conjunction with rigid clutch discs, this displacement can cause idling noises and increased profile wearing in critical cases. One remedy to this problem is the displacement correction clutch disc, which enables radial displacement of the hub and thereby revents potential radial forces in the idling and low load ranges. The efficiency of the pressure springs in the displacement correction clutch disc is limited to the low load range."

In my opinion, BMW failed to make the input shaft long enough, and they failed to properly damping the clutch. In fact, there is no clutch damping or cushioning. They put a 1950's clutch into a modern day motorcycle. It is no wonder we are having problems. Maybe BMW figured that the problems would come up after warranty. It is hard to believe that BMW didn't know about this. After all, the problem has been there since the 1970's. It is only in 2014 that BMW decided to change the clutch.

I also believe that the RSR clutches are a movement in the right direction. They will probably reduce input shaft wear problems, gear crashing, CV joint problems, and maybe even reduce ring bearing problems. I can't see any harm in using their clutches (except they are more expensive). I know of a couple people who have used the RSR clutches and they don't seem to have drive train problems thereafter. But, I only know a few, so it is hard to determine if their calculations of spring damping was done correctly.

gsaddict · Dec 23, 2013

jammess said:
I've been trying to shift smoothly for 45K miles and I just can't seem to manage it unless I ride with the throttle position lever (choke) in the detent. Sometimes I get it right but only sometime. Other two beemers with cable operated clutches no problem. Probably just me and my poor hand/feet co-ordination. Reminds me of the driving range, sometimes I can do no wrong and other times.......

Couple of thoughts...
Is the linkage and pivot clean and lubricated? Is it adjusted correctly for you?
What kind of footwear are you wearing? different types?
I have to make more positive movements with my hiking boots than with my GS boots.

Checking for spline wear 1999 R1100S

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