Clutch Spline Failure Analysis

[AndyRR]

I have spent spent way way too much time thinking about this issue. Several times I woke up with an AH HA! It's neat the way the right brain takes over and comes up with a solution subconsciously.

The trans input shaft is allowed to flex because of its diameter to length ratio and its hollow.

Given the relative thickness of the shaft to the length outside the bearing, I don't think it's flexing. I'm not an engineer and I can't prove it, but I just don't see it happening. I DID see abnormal signs of wear on the input shaft bearing.

It should be easy to check the dimension or run out of the input shaft to the trans to engine mating surface, at the trans side.

I think I posted pics of this measurement in my "Spline replacement time" thread. I measured .007" of runout (.014 TIR). I didn't notice any abnormal wear on the flywheel.

Perpendicularity was more difficult to measure accurately, but my measurements of the engine case to the front clutch housing indicated that it was OK.

With regards to fixing the problem, I am correcting three issues.
1. Correcting the alignment issue with offset dowels.
2. Lengthening and hardening the input shaft to gain 0.2" of engagement. (My fingers are crossed that I will have two shafts this afternoon!)
3. Lengthening and hardening the clutch hub to gain 0.3" of engagement. (still waiting on this. )

I suspect that only correcting #1 and replacing parts with stock would give a good result, but 2 and 3 add suspenders to the belt if you know what I mean. I had to replace the parts anyway and they correct obvious deficiencies in the OEM design for prices close to OEM. I don't have final pricing yet, but in quantity, I hope to be able to provide the shaft for around $400.

[keithbw]

AndyRR

I'm pretty sure I'm going to go with the RSR clutch, my splines are showing wear already at 12,000 miles.
Maybe the sprung clutch will help and at least I can get the bike out of the garage.
I posted pictures on the other thread. If you still want the stock one I will send it your way.

[oiasghar]

Just found this link http://www.rbracing-rsr.com/bmw_clutches.html posted on bmwsporttouring.com. What is interesting is the link
http://www.rbracing-rsr.com/downloads/d ... schift.pdf to the PDF which looks like a BMW Technical Service Bulletin. Funny when last year I got the Spline lube from the dealer, I got the GL 261 but ended up using Honda Moly. If I had known about this I would have kept my RR. Crap!!! Love the F800ST but the RR was very special

Just saw AndyRR above me posted about the RSR clutch. Argh!!! I always find things out a little late.

[vwdoctor]

After reading through 10 pages and hoping to get to something definitive, the thread just dies?

[sweatmark]

After reading through 10 pages and hoping to get to something definitive, the thread just dies?

That period (2009ish) marked the transition of bulletin board focus from the 1150s to 1200s. Those of us cranky or crazy enough to keep our 1150s decided to deal with any potential problems if and when they occurred. Others moved to the then-new Hexheads and improved BMW engineering and/or quality control.*

This is still a valid topic for discussion IMHO. At least for us 1150-forever types.

* full disclosure: my personal disgust with the clutch spline, iABS, final drives, etc prompted me to trade one of our R1150s for an F800, just to be on the safe side.... Um, the F800 is in the shop today for another recall.

[Rags]

Had it happen on my 04 R1150RS at about 40K miles

I was invoiced for $4,000 +/- (outside of warranty) and the SF BMW Mgr got me a discount of $2,000.

The Tech diagnosed the problem as misalignment tween motor/trans.

I had the same misalignment problem on my Porsche Cayenne that blew a interim drive gear assembly @ 55K - no warranty or discount.

It was a known unacknowledged problem

Manufactures get intentionally blind when not health & safety related

Rags

[OU812]

These Germans sure are stingy about admitting to any problems with their products.
I know all about them with my own issues.

[vwdoctor]

I think at this point we can all agree that 6 speeds with partial engagement of the clutch suffer from much higher rate of failure than any other BMW bike in history. I am basing this on extensive reading and research of all available posts mostly quoted in the beginning of this thread, and some recent ones.
Although I know this is not scientifically valid data, the accounts are many and undeniable. And if you assume (conservatively), that for every one you read about there are at least 5 that you don't (at least 50% of "normal" people have no idea what a spline looks like, and to some "bike blew up" is the description of the problem) numbers are really getting big.
It looks like the only real things done to attempt to fix the problem were the offset engine transmission pins and that bike is totaled less than 10k miles after the modification. Number of Bruno clutches is unknown at this point since nobody on any forums I have been mentioned that they had one installed.
In the interest of full disclosure I am working on the modified clutch hub due to this issue that I noticed with my bike, but I would still like to gather all available data from the past.
I appreciate the feedback.
Esmir

[Rags]

These Germans sure are stingy about admitting to any problems with their products.
I know all about them with my own issues.

To be fair, it's not only the Germans; It can be Japanese (Nikon cameras & Toyota) or American (GM 's latest revelation of 2008 failures)

When it concerns health & safety , there can be large fines like with Toyota & GM.

Otherwise the manufacturers pay little attention

For the motos, I would suggest not "loading" the gears - choose a lower one with higher rpms

Rags

[DKSTRWER]

Agreed with Rags, probably because engine impulses at low revs impact the driveline etc. Years of studying spline failures suggests the core issue is misalignment. Second is corrosion. Lube appears to have less to do with it other than preventing rust/corrosion; the fore and aft movement on the shaft is very slight, maybe 1/8" and only occurs during clutch actuation. The shaft with the longer splines or a clutch mod that shims the clutch splines will help parts last longer as either enables full engagement. The shaft could last longer through several clutch replacements. An experienced tech in these matters suggests that if spline failure were to occur at say 50k with either of the upgraded parts you might get 75k.

As BMW does not release accurate tech drawings for trans cases or engine cases it would be next to impossible to know if the trans case, engine case, or both are out of spec. The two cases are dowel-pinned to make them fit together without provision for alignment. My guess is that there is an allowable tolerance for both parts and if one is unlucky, his motorcycle might have parts that are out to the max in opposite directions on the two parts which gives 2X allowable and results in failure.With proper alignment and lube the clutch splines should last the life of a clutch and shaft splines the useful life of the tranny. The percentage of the bikes that have non-corrosion related failures is really small. If you are concerned, pull the trans out and look at the splines. If they are good, and they likely will be, you should be good to go for the life of the clutch wear.

The main issue again is to fix any misalignment, then to prevent corrosion. Then even the stock parts should last well enough, say 50k. The clutch splines are not as hardened as the shaft's, especially the longer upgrade shaft, and can be expected to strip out first.

www.brunos.us

http://www.sunshinecoast.ca/bmw/InputShaft.pdf

https://www.youtube.com/channel/UCRZEzm ... nVKe7d-wIg

http://www.affordablebeemerservices.com/bmwthoughts/

https://www.youtube.com/watch?v=vvQaZhh ... FpX3zuxT88

Or...hoot it, get a Sporster (2007+):
http://www.jamesrussellpublishing.biz/s ... r1200.html

[sykospain]

I just noticed that the current R-series bikes all have wet clutches located in a completely different layout to the design of BMW Motorrad's dry clutches which the firm persisted with for around fifty years with no noticeable improvements.

Now there's a thing. So they'll never acknowledge any problems with spline wear.. what a firm.

AL in s.e. Spain

[DKSTRWER]

Chris Harris ~ BMW Service - Clutch / Transmission Spline Failure Explained

https://www.youtube.com/watch?v=Jx3e0gqzylY

[DKSTRWER]

BMW Service - Clutch / Transmission Spline Failure Explained (Chris Harris)

https://www.youtube.com/watch?v=Jx3e0gqzylY

[P_Jensen]

The water cooled models with the wet clutchs have there own teething problems, with the "anti-hop" feature requiring a specfic oil in order to avoid problems with engagement.

[Keppelj]

I have two pals with high mileage 02 RRs, one with 130k miles, neither with a spline problem. Ride West BMW in Seattle, where I've done service business, says it occurs in a small percentage of all oil-heads, about 10% of them, and they wouldn't prophylactically do the fix without first diagnosing the failure. Hmmmm.

[peels]

I have two pals with high mileage 02 RRs, one with 130k miles, neither with a spline problem. Ride West BMW in Seattle, where I've done service business, says it occurs in a small percentage of all oil-heads, about 10% of them, and they wouldn't prophylactically do the fix without first diagnosing the failure. Hmmmm.

prophylactically

take a bow.
you scored word of the day.

[Keppelj]

Can't take the credit. Bow goes to the service guy.

[Oilhead]

says it occurs in a small percentage of all oil-heads, about 10% of them, and they wouldn't prophylactically do the fix without first diagnosing the failure. Hmmmm.

Did your mechanic really say 10%? That's a lot! I certainly would not consider that a small percentage.

[CycleRob]

For bikes in the 2 wheel BMW price range, NONE of them have this kind of failure!! Not even 1 percent!!

[kirby]

For bikes in the 2 wheel BMW price range, NONE of them have this kind of failure!! Not even 1 percent!!

I agree completely!!!

This whole subject has attained mythical proportions!!