Checking for spline wear 1999 R1100S

[roger 04 rt]

I understood from the driveline people at Toyota in the 1980s that they were developing this to get rid of transmission "chuckle" when idling in neutral with 4 cyl engines. They never mentioned durability.

But why do some bikes have essentially zero wear and others rub out the splines in comparatively few miles? I don't think it is driveline abuse/driving habits. My 2000 R1100RT is being driven by an elderly driver (me) @ modest rpms and high gears, yet showed no wear.

Do those of you who have had a spline strip-out consider yourselves as aggressive drivers? or is it just a random failure?

Doesn't it seem like this problem is multi-dimensional? An under-designed hub spline pair will be more susceptible to errors and loads.

In your case, modest rpms, any gears, probably never loads the transmission input more than 1/4 or 1/3. Think of how many systems work fine until you start to reach the design limit--the Tacoma Narrows Bridge, which at the right high load oscillated itself to death.

[Blacque Jacque Shellacque]

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.......

IMHO I think the problem is due to the lack of a flywheel. When the clutch is pulled and the throttle closed, the engine rpm's drop like a stone very quickly. It's easier to get a nice shift at higher rpms's. In contrast, my 84 R80, while having the lightened flywheel maintains higher rpm's during the upshift, allowing the engine speed to match transmission speed much closer. I find it almost impossible not to get a smooth shift with the R80. Perhaps not scientific, but that's how it appears to me.

[23217]

The flywheel is part of the problem. But, probably not for reasons you might think. The flywheel acts as a heat sink for the the clutch assembly. If the clutch assembly overheats, it will lead to warpage, sagging, vibrations, etc. And, this leads to input shaft and drive train problems.

A big part of the problem is that we have some clutch slippage, and this leads to more heat and warpage. The main reason for the clutch slippage is because the BMW clutch plates are not segmented. Segments are curved plates between the inner metal clutch plate and the friction material that will allow friction material to conform to any irregularities in the plates. This results in more contact area, less friction, and less heat. Part of Anton's success of not having repeat failures is because he is replacing the clutch assembly. Any warpage in the clutch assembly will just result in a repeat failure of the input shaft. And, just because the plates do not look warped when cold, does not mean that they do not go back to their warped state when heated up. So, replacing the clutch assembly with the input shaft is wise.

One of the differences between the 1100 and 1150, is that the 1100 have a 180mm disc and a 1.75mm diaphragm spring. With the 1150's they reduced the size of the clutch plate to 165mm and increased the diaphragm spring to 2.00mm. Obviously, BMW knew that they had clutch slippage and plate warpage issues, and that was leading to input shaft failures. They believed a smaller clutch plate would have less warpage. And, with a stiffer diaphragm spring, this would solve the input shaft failure problem. Their error was that they still had clutch slippage, and more pressure meant more heat and more warpage. So, the end result was more input shaft failures. Or, at least this is my theory. I don't know if it is possible to put in a 1100 clutch assembly and input shaft into a 1150? But, that might help reduce some of the failures of the 1150's. As for Roger's question, my theory is that the stiffer diaphragm spring is cause the 5% wear on the inside of the plates, and I am assuming that there is some plate warpage that would contribute the the 5% increased wear pattern on the inside. Maybe there is only plate warpage when the plate is hot with pressure on it. Something to think about.

Changing the flywheel probably is not a reasonable option. Solving the problems inside the clutch can make up for the lighter flywheel. Specifically, less clutch slippage and heat.

[roger 04 rt]

The flywheel is part of the problem. But, probably not for reasons you might think. The flywheel acts as a heat sink for the the clutch assembly. If the clutch assembly overheats, it will lead to warpage, sagging, vibrations, etc. And, this leads to input shaft and drive train problems.

A big part of the problem is that we have some clutch slippage, and this leads to more heat and warpage. The main reason for the clutch slippage is because the BMW clutch plates are not segmented. Segments are curved plates between the inner metal clutch plate and the friction material that will allow friction material to conform to any irregularities in the plates. This results in more contact area, less friction, and less heat. Part of Anton's success of not having repeat failures is because he is replacing the clutch assembly. Any warpage in the clutch assembly will just result in a repeat failure of the input shaft. And, just because the plates do not look warped when cold, does not mean that they do not go back to their warped state when heated up. So, replacing the clutch assembly with the input shaft is wise.

One of the differences between the 1100 and 1150, is that the 1100 have a 180mm disc and a 1.75mm diaphragm spring. With the 1150's they reduced the size of the clutch plate to 165mm and increased the diaphragm spring to 2.00mm. Obviously, BMW knew that they had clutch slippage and plate warpage issues, and that was leading to input shaft failures. They believed a smaller clutch plate would have less warpage. And, with a stiffer diaphragm spring, this would solve the input shaft failure problem. Their error was that they still had clutch slippage, and more pressure meant more heat and more warpage. So, the end result was more input shaft failures. Or, at least this is my theory. I don't know if it is possible to put in a 1100 clutch assembly and input shaft into a 1150? But, that might help reduce some of the failures of the 1150's. As for Roger's question, my theory is that the stiffer diaphragm spring is cause the 5% wear on the inside of the plates, and I am assuming that there is some plate warpage that would contribute the the 5% increased wear pattern on the inside. Maybe there is only plate warpage when the plate is hot with pressure on it. Something to think about.

Changing the flywheel probably is not a reasonable option. Solving the problems inside the clutch can make up for the lighter flywheel. Specifically, less clutch slippage and heat.

Thank you for the added input, this is very interesting.

Can you shed any light on how the splines wear in the angled pattern below. It looks like about a 5 degree angle on the tooth. It's hard to imagine how that happens.

[nrpetersen]

Anything but radial misalignment..............!

Explain the excessive main bearing wear in a peculiar direction found at

http://forums.bmwmoa.org/showthread.php?56977-Clutch-and-input-shaft-spline-%C3%94%C3%87%C3%B4-need-advice-please/page5[/URL]

Later - I reread that series of posting but nowhere did I note the excessive main bearing clearance that was measured with that setup. As I recall it was about .013 clearance (WOW!) in the 10 o'clock - 2 o'clock axis, and much more reasonable (like .002") in the 1 o'clock-7 o'clock axis.

Somewhere later I did post this but I can't find it now.

[jammess]

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.

Morning and Merry Xmas Adict,
I am referring to my '04RT with the hydraulic clutch when I talk about smooth shifting. My '94RSL or '81R100 with cable operated clutches cause me no grief at all nor has any BMW mc I have owned since '76.

I am going to decide by this spring if I want to keep the '04 or sell and if I keep it I am going to install an RSR clutch for sure. I wish I had made this move when I did a spline lube at 35K miles.

[jammess]

Morning and a merry one Roger,
Yes, I think you are somewhat backwards when you say that torque at higher RPMs produce the potential for more spline wear. Sure the motor produces higher rotational torque at >RPM but that can only effect spline stress under load if the transmission is in a higher gear with associated : All of the 45K miles on my '04RT are long distance highway miles in sparsely populated areas of the western states. Never have I used the bike for stop and go heavy traffic riding, never! Also, of that 45K miles not even as much as 1K miles has the machine been ridden in 6th gear. I am sure this style of riding has resulted in negligible spline wear as seen under a magnifying glass. Also, I just can't believe that BMW would have produced transmission or engine parts that when married together produce any kind of axial mis-alignment that would result in the spline failures we have seen over a period of years. I just can't accept that!

As to your question about how the splines wear with that strange 5 degree angle? That is indeed an interesting question to which I wouldn't even attempt an answer what with my limited mechanical background. In fact that is the most nagging of questions when it comes to this spline wear issue, imo. What I would give to know if BMW has an answer. Probably their answer is a wet clutch. lol..lol

[roger 04 rt]

Morning and a merry one Roger,
Yes, I think you are somewhat backwards when you say that torque at higher RPMs produce the potential for more spline wear. Sure the motor produces higher rotational torque at >RPM but that can only effect spline stress under load if the transmission is in a higher gear with associated

Jim, it's entirely true that at a steady speed, torque at the transmission input will be higher in a higher gear. But as I mentioned, at 65 mph the difference between 5th and 6th is 18 and 24 ft-lbs respectively. That's a mere fraction of the input torque that you'd have, for example in 2nd or 3rd gear with a WOT acceleration through to 6500 rpm. During that acceleration, the transmission input experiences the full maximum torque of the engine (74 ft-lbs at 5500 rpm). That seems to me by far the greatest load. RB

[jammess]

Jim, it's entirely true that at a steady speed, torque at the transmission input will be higher in a higher gear. But as I mentioned, at 65 mph the difference between 5th and 6th is 18 and 24 ft-lbs respectively. That's a mere fraction of the input torque that you'd have, for example in 2nd or 3rd gear with a WOT acceleration through to 6500 rpm. During that acceleration, the transmission input experiences the full maximum torque of the engine (74 ft-lbs at 5500 rpm). That seems to me by far the greatest load. RB

Hi Roger,
I don't mean to give the impression that I open the throttle, WFO, when accelerating up through the gears, not at all. I ride with a light touch on the throttle at all times, takes me awhile to go from stopped to 65mph. I don't abuse my equipment and I agree that going through the gears with heavy throttle at high revs would subject the trans input to high and un-necessary torque. I'm talking about steady state cruising at high RPM (4 - 6K) versus low revs say.. 2.5 - 3K. At low revs the drivetrain sees more power pulses from rocking couple caused by the nature of the beasts connecting rod offset. I, and many others, believe these big flat opposed twins are happiest at high revs. Yesterday I took the '94 RSL out for a ride down the Oregon coast and never once did it see 5th gear at speeds from 55 to 70 mph. Revs were anywhere from 3.5K to 5K in 4th.

Was a beautiful ride with temp around 53 degrees in bright sun with no wind, FANTASTIC! And so was the cinnamon roll at the world famous Sugar Shack Bakery at Reedsport, OR.

[roger 04 rt]

I wasn't so much thinking about your personal riding style as I was making the general observation that although gear selection does affect input shaft torque while cruising, the loads at the input shaft during hard acceleration could be a factor for some who ride aggressively since those input torques can easily be 3-4X the cruising torque. Okay, that's beaten to death.

All this discussion aside, I need to open mine up, clean & grease, and establish a benchmark. And replace the slave cylinder while I'm there. (And replace my add-on FPR with a 3.5 bar in the fuel distributor while the tail is up,)

[GSAddict]

Check out his pictures at 130,000m

http://www.advrider.com/forums/showthread.php?t=943596

[cele0001]

bump.