Driveshaft Recall Update

[Rob Nowell]

On 7/3/2024 at 3:28 PM, Bruno From Québec said:

I'm curious to know if anyone was able to obtain a driveshaft to replace themselves.

If they're willing to do it for free, ...why?  But that's just me.

[dirtrider]

3 hours ago, Rob Nowell said:

If they're willing to do it for free, ...why?  But that's just me.

Afternoon Rob

 

There are a number of us BMW owners that would rather do the repairs ourself than to trust the BMW dealer to do it correctly without shortcuts or missed steps. Not that most BMW tecs are careless but "things happen". Like a tec gets pulled off a job in the middle of a critical procedure to go help another customer, or quitting time comes part way through a job so next morning something that should have been done gets overlooked, or the motorcycle is in pieces blocking a lift with a part that should be replaced not available so the original gets re-installed to get the lift free & the job out of the shop.  

 

Lots of reasons but those usually only bother riders that know how the system works or have worked on a number of previously dealer serviced motorcycles. For most riders they just trust the dealer & believe what the dealer tells them is the truth.  

 

There are some very good dealer tecs out there that have good work ethics & take great care to do things correctly but unfortunately not all are that way.  

[dirtrider]

2 hours ago, Dave_in_TX said:

DR, I would be interested to what chain bikes that can go that far and what your chain maintenance routine. I have seen similar claims before but on many forums related to chain driven bikes, 12k seems common although a few outliers are reporting chain life similar to what you are experiencing.

Afternoon Dave

 

I won't go into exact motorcycles but most that get 15k plus on are lower powered using "O" ring chains & quality sprockets. I have a BMW 800GS that went 20k on the original chain (3 chain adjustments) & one new front sprocket at 10k, even then I just replaced it (+ sprockets) as I was going on an on-road/off-road extended trip (the chain rear sprocket still looked good). I'm a believer in new front sprockets between chain changes as that little bugger has few teeth that sees a lot of chain links go over it. I used to reverse some but a since a lot of newer bikes use offset front sprockets I just install new & if I am happy with the OEM I use that as aftermarket sprockets can be a crap shoot.  

 

Because I ride a lot of dirt/sand on the my chain bikes I don't exactly lubricate using chain lube or any oily residue type lubrication. I typically clean the chain after a hard weekend of usage using WD-40, then allow the WD-40 to flash off (dry) then use spray DuPont Teflon on the chain (the carrier liquid flashes off leaving a mostly dry Teflon coating that does not attract or hold dirt or grit)

 

On the "O" ring/X-ring type chains I NEVER EVER  power wash on the chain (that will kill a chain in no time), I also don't like using any type of solvent that will soften or ruin the "O" rings or wick in past the "O" rings.

 

I can't keep tires on a motorcycle and my brake life is usually poor but I have the chain life thing working pretty good.  

[RadioFlyer]

In any event a chain, unlike a shaft, gives plenty of warning that it is nearing end of life and in that sense inspires more confidence. Also no manufacturer ever recalled 440,000 bikes for a chain drive issue.

[dirtrider]

1 hour ago, RadioFlyer said:

In any event a chain, unlike a shaft, gives plenty of warning that it is nearing end of life and in that sense inspires more confidence. Also no manufacturer ever recalled 440,000 bikes for a chain drive issue.

Afternoon RadioFlyer

 

Not 440,00 motorcycles but BMW even screwed the chain drive up.

 

**Notice of recall 10V-274** Subject: Replacing Drive Chain and Sprockets Details: Aftersales Solution: BMW Motorrad has received reports about broken drive chains. The problem is due to quality fluctuations in the manufacturing process of the drive chains and those chains that were manufactured during specific production periods must be replaced. If the drive chain breaks, it can lead to safety critical riding situations. Under a worst case scenario, the rear wheel could lock up if the broken drive chain becomes trapped between the wheel and the frame. Production Solution: Drive chains from a dependable production process are installed at the factory. Model: F 650 GS (K72, 0228), F 800 GS (K72, 0229

[marcopolo]

2 hours ago, Rob Nowell said:

my dealer told me every 36k after this first 36k

Yes.  The Service Information Bulletin, outling the recent changes to maintenace schedules for all K5x bikes, model year 2023 and older, specifies the driveshaft is to be replaced every 36,000 miles (that's miles of use of the driveshaft, which is not necessarily the same as the mileage on the bike's odometer, such as for a shaft that's already been replaced.  Dealers are advised to check  the mileage on the shaft itself).  Obviously, if a shaft fails one of the periodic tests, evety 12,000 miles, it's to be replaced then.

[RadioFlyer]

29 minutes ago, dirtrider said:

Afternoon RadioFlyer

 

Not 440,00 motorcycles but BMW even screwed the chain drive up.

 

**Notice of recall 10V-274** Subject: Replacing Drive Chain and Sprockets Details: Aftersales Solution: BMW Motorrad has received reports about broken drive chains. The problem is due to quality fluctuations in the manufacturing process of the drive chains and those chains that were manufactured during specific production periods must be replaced. If the drive chain breaks, it can lead to safety critical riding situations. Under a worst case scenario, the rear wheel could lock up if the broken drive chain becomes trapped between the wheel and the frame. Production Solution: Drive chains from a dependable production process are installed at the factory. Model: F 650 GS (K72, 0228), F 800 GS (K72, 0229

 

Only 1916 units affected by that recall. 

[RTinNC]

4 hours ago, Rob Nowell said:

my dealer told me every 36k after this first 36k

For some reason the 2024’s are every 50k

[RTinNC]

3 hours ago, dirtrider said:

Afternoon Rob

 

There are a number of us BMW owners that would rather do the repairs ourself than to trust the BMW dealer to do it correctly without shortcuts or missed steps. Not that most BMW tecs are careless but "things happen". Like a tec gets pulled off a job in the middle of a critical procedure to go help another customer, or quitting time comes part way through a job so next morning something that should have been done gets overlooked, or the motorcycle is in pieces blocking a lift with a part that should be replaced not available so the original gets re-installed to get the lift free & the job out of the shop.  

 

Lots of reasons but those usually only bother riders that know how the system works or have worked on a number of previously dealer serviced motorcycles. For most riders they just trust the dealer & believe what the dealer tells them is the truth.  

 

There are some very good dealer tecs out there that have good work ethics & take great care to do things correctly but unfortunately not all are that way.  

I guess I’m one of the lucky few who have a very good dealer and an excellent tech.  The same master technician has been the only one working on my bikes for the last 10 or 15 years.  He knows me, he knows my bikes, and I absolutely trust him. But I’m sure that’s not the case with all dealers.

[Twisties]

Then there are the dealers that are downright dishonest.  But, it's all good.  Caught them churning parts they charged us for onto EBAY, but the outcome was we learned to do our own service.  It was a one dealer market and that was pretty much that.  So, now 17 years and IDK, between the two of us about 200k miles, into our BMW experience we've saved many thousands of dollars on routine maintenance.  Before you ask, the dealer is long gone out of business and no need to name names.

 

I would never have bought another BMW, but we moved to S. Oregon and Hansens was absolutely the best.  So, I agree, it depends on the dealer.  

 

Now we've been dealing with Grand Junction, CO and they've been fine.  But we haven't been in since the change in ownership, so we'll see.  Both bikes had their drive shafts replaced in the original service campaign.  IDK if we'll be up for riding them 5 hours each way every 12k miles to have them checked, even if they will do so without a paid service. 

[JCtx]

The comment about shaft angle adding stress to the shaft was very valid. GS bikes have a steeper angle, due to being lifted compared to my R, RSs, and RTs, do they're obviously more prone to (stress) failure in the long run than other street models. And on top of that, they're much more likely to be subjected to other undesirable use (and abuse), like jumping, crossing streams, ride in rain/mud, etc. Finally, just in case my bike wasn't lubed properly during production, will check the splines on the next tire change, which should be near 10K miles on the clock. Will continue to follow this thread for added information. Very useful. Thank you.

[dirtrider]

6 hours ago, JCtx said:

The comment about shaft angle adding stress to the shaft was very valid. GS bikes have a steeper angle, due to being lifted compared to my R, RSs, and RTs, do they're obviously more prone to (stress) failure in the long run than other street models. 

Morning JCtx

 

The thing about the drive shaft angle is that the rear angle stays pretty straight even at full droop. This is due to the rear drive pivot location & the torque arm pivot locations. 

 

The front does get to a fairly extended angle at full droop. 

 

But it's the rear U joint that typically fails, if it was a high working angle induced  failure then it should be the front U joint failing not the rear. 

 

On a drive system with this much delta between the front & rear U joint working angles it really should have a front CV (or double-cardan) but it only achieves the extreme angle delta at full droop so they are not ridden there for long  & the rear traction is probably low at that extreme.  

 

[Scotto336]

Interesting point D.R.  One theory (right or wrong) would be that the rear U joint bearings are more prone to moisture ingress ( pressure induced or not) since the water will be sitting at the lowest point.  Bearing failures that I've seen on line appear to involve corrosion.  Rear bearings may also take somewhat more of a beating from potholes and such.

Scott

[dirtrider]

52 minutes ago, Scotto336 said:

Interesting point D.R.  One theory (right or wrong) would be that the rear U joint bearings are more prone to moisture ingress ( pressure induced or not) since the water will be sitting at the lowest point.  Bearing failures that I've seen on line appear to involve corrosion.  Rear bearings may also take somewhat more of a beating from potholes and such.

Scott

Morning Scott

 

Yes, that moisture environment on the rear low end  is probably the most logical & seems BMW has addressed this (or tried to anyhow)  with the addition of that drain wicker-bil. 

 

But, the big BUT! here is, then why STILL the 36K drive shaft replacement requirement & even a drive shaft re-grease replacement interval on the new 1300????? There is some sort of basic design flaw, or swing arm packaging size limitation, figuring in somehow.  With the rear tire having to clear the cutout in the swing arm that kind of limits the U joint size that will pass through it (unless a much higher dollar 2 piece drive shaft is used). If they try to off-set the rear drive farther off-center to go with a larger cut out that will drastically increase the twisting force on the alloy swing arm & pivot joints so that will be difficult to do & keep costs down. 

 

The water intrusion explains the corrosion & sticking spline part but not the early failure events even after the wicker-bil  drain is added. 

 

This is a more complex issue & if it was easy to identify & rectify then BMW would have done that with additional venting or drive shaft re-design. 

 

There is more to it, & BMW will never admit anything,  so about all we can do is to watch where the future BMW drive line improvements go on the future motorcycles. How they take the rear drive into the future will tell us a LOT. 

 

My guess, based on my engineering background, is future designs will see more robust U joints, (probably larger if they can somehow package them), some type of improved anti-corrosion coating on the splines,  possibly slightly changed rear swing arm angles (that will be difficult & still retain the good anti-lift & anti-dive that the system has now.   And/or possibly different shaft joint type. Or possibly even going back to a sliding mid-shaft spline. 

 

The auto companies fought this standard U joint thing for years on 4 wheel drive solid front axle trucks. Even with CV joints the auto industry has been forced to go with more costly premium CV joints, and/or premium high angle non-plunging CV joints. 

 

As a number of us old time engineers have bantered around for years as we have seen similar problems come & go on the automotive side-- If you can't properly seal & properly vent the environment  then leave it totally open & properly seal the joints & sliding parts. 

 

I'm still not a big fan of single sided swing arms but if you want the sleek looks, that great anti-lift & anti-dive of an articulating rear drive, ease of tire changes, with narrow packaging then that is the easy button.  

 

OR, use some type of electronic torque limiting like the automotive industry has had to use for some problem child's. 

 

[Mellow]

11 minutes ago, dirtrider said:

But, the big BUT! here is, then why STILL the 36K drive shaft replacement requirement & even a drive shaft re-grease replacement interval on the new 1300????? There is some sort of basic design flaw,

It's a u-joint...without a grease zerk.. so, defective by design.

 

Cars have bigger ones, less angular extremes, zerks and also less RPMs than our rides...

 

Every drive shaft bike has some implementation of a u-joint.  Either a full one on the transmission output shaft like ST1300s and some GL1800s or welded to the shaft like BMW and newer goldwings.

 

They are like wheel bearings... they may last forever and many last a long time, or fail due to certain conditions that cause corrosion, heat, etc... You can call it a design flaw but no different than calling a chain drive a design flaw as the chains wear out.

 

Ride more.... Worry less...

[dirtrider]

7 minutes ago, Mellow said:

It's a u-joint...without a grease zerk.. so, defective by design.

 

Morning Mellow

 

Not necessarily, most modern US vehicles (that still have U joints) have no grease fittings or pin greaser sockets. My truck didn't come with a mandate to replace the drive shaft at 36K or to grease the slip yoke at 12K.

 

 

[Mellow]

7 minutes ago, dirtrider said:

Morning Mellow

 

Not necessarily, most modern US vehicles (that still have U joints) have no grease fittings or pin greaser sockets. My truck didn't come with a mandate to replace the drive shaft at 36K or to grease the slip yoke at 12K.

 

 

But.. how many times have you seen a vehicle - especially 4wd.. with a drive shaft hanging off touching the ground.  Vehicles still have bigger ones that don't spin as much as bikes do.  Of course, move of those are exposed vs ours which are enclosed so you'd think ours would last a lot longer.

 

The real questions is how many have actually failed at what mileage.  My ST1300 failed at 50,000 miles and I noticed in the garage.. some go well over 100k and owners will replace just to avoid a possible failure, some fail at 70k... some.... have yet to fail at all......  We don't really have any real numbers.. just the panic associated with the new bmw replacement specs probably spurred on by a failed one that cause a law suit.

 

I'll check mine as 24k and ever 12 after that but probably won't replace 'til the 48k milestone... mostly due to my ST1300 history more than anything...

 

I have an RT and GSA and ride both as touring bikes so the GSA will probably get 1% more abuse than the RT..

[Dave_in_TX]

37 minutes ago, dirtrider said:

 

But, the big BUT! here is, then why STILL the 36K drive shaft replacement requirement & even a drive shaft re-grease replacement interval on the new 1300?????

I think this us typical BMW. When you can no longer pretend the problem doesn't exist, then overreact or be very conservative.

 

Reminds me of the "lifetime" of fluid in hexhead final drives. When problems arose, the reaction was to go to a fluid change at 12k intervals. I suspect a 24k interval would have worked as well.

[dirtrider]

15 minutes ago, Dave_in_TX said:

 

Reminds me of the "lifetime" of fluid in hexhead final drives. When problems arose, the reaction was to go to a fluid change at 12k intervals. I suspect a 24k interval would have worked as well.

Morning Dave 

 

True, probably 24 K or even higher would work after the first or second changeout. From what I have seen on those early fill-for-life drives it took at least 2 changes & sometimes 3 to get all that high moly content goop out of the drive. High moly is good for ring & pinion high tooth load protection but not so good for the bearings. (what usually fails on the BMW final drive? The gear teeth or a bearing?   

 

 

[RTinNC]

  Need more popcorn 

[Mellow]

Just now, RTinNC said:

  Need more popcorn 

They don't make that much popcorn...too busy using it for ethanol...

[Scotto336]

Stating the obvious, trying to manage design and manufacturing issues post launch are tricky and very often involve a compromise solution due to cost.  Safety issues usually get more attention as regulators become involved.  I hope no one has been injured due to driveshaft failure.  Lubing splines, checking balance, adding a vent and periodically changing shafts may prove to be enough in the eyes of BMW.  

[dirtrider]

1 hour ago, Scotto336 said:

Stating the obvious, trying to manage design and manufacturing issues post launch are tricky and very often involve a compromise solution due to cost.  Safety issues usually get more attention as regulators become involved.  I hope no one has been injured due to driveshaft failure.  Lubing splines, checking balance, adding a vent and periodically changing shafts may prove to be enough in the eyes of BMW.  

Afternoon Scott

 

 

BMW isn't checking the balance with the drill & tone ring test. They are looking for a very slight acceleration deceleration in the driven tone ring as the spinning U joints work.  That is one reason they spec out a brushless drill as the force driver due to it's very controlled constant RPM. 

 

A shaft U joint failure lock up sure could cause a sudden rear wheel lock up. I think they have had a few reported  on the wethead. 

 

I ride with a rider that had a catastrophic U joint failure on a hexhead 1200 GS a couple of years ago. I was right in front of him doing about 60 mph on fairly straight sandy two track when he suddenly disappeared from my mirrors. I backtracked & found him standing next to his laid over 1200GS. 

 

I asked what happened & he told me that his rear wheel suddenly just locked up (he thought it had a trans issue & was in two gears that the same time). I asked if he was OK & if he went down hard. He told me he didn't go down & rode it out (he is a very good off-road rider). I said why is the bike on it's side, he laughed & said this soft sand won't allow the side stand or center stand to hold it up. There was probably a 200' wiggly line from the locked up rear wheel dragging in the sand. 

 

The scary part was we had just previously entered that two track from a hi-way that we were running close to triple digits.   THAT, would have been a difficult one to just ride out!

 

I won't go into it but recovering that big 1200 GS with a locked up rear wheel was a task to remember as we were a long ways from home & a long way from enough tools to free the locked up shaft then tow it out. 

 

 

 

 

[marcopolo]

That's why I suspect the BMW legal department had just as much to do with these new driveshaft maiintenace procedures, as the engineering department.

 

Fascinating explanation of the driveshaft test, dirtrider.  As soimeone with next to no mechamical aptitude, just what does a slight acceleration/deceleration in the tone ring tell them?

[dirtrider]

57 minutes ago, marcopolo said:

That's why I suspect the BMW legal department had just as much to do with these new driveshaft maiintenace procedures, as the engineering department.

 

Fascinating explanation of the driveshaft test, dirtrider.  As soimeone with next to no mechamical aptitude, just what does a slight acceleration/deceleration in the tone ring tell them?

Afternoon Mark

 

Obviously it is a way determining the U joint resistance at different shaft clocking's as it spins.  

 

It must be pretty sensitive as a brand new (not broken in) drive shaft & even some cold drive shafts usually won't pass the spin test. 

 

The spinning test wheel has a large number of notches (teeth) on it (just like a smaller ABS wheel speed sensor tone ring) & actually uses a type of wheel speed sensor to output the spinning test wheel RPM's precisely at any given rotational point. 

 

There is software (including software updates) involved so it is smart enough to determine (possible) existing U joint issues. 

 

This probably isn't known by non technical people but U joints running at anything other than a 0° angle speed up & then slow down the output side in relation to the input side twice per revolution, the greater the U joint working angle the more the output side speeds up & slows down twice per full revolution  (this is why drive shaft phasing alignment is important at drive shaft installation). 

 

This is basically why most front wheel drive cars use CV (Constant Velocity)  axle shaft joints, with the front wheels turned to near the steering stops the vehicle would have a pronounced pulsing feel as the wheels rotated if standard U joints were used as the outer joints would have a LOT greater working angle than the inner (transmission end) joints so that speed up/slow down twice per revolution couldn't cancel itself out with matching inner to outer U joint working angles. 

 

 

[Scotto336]

1 hour ago, dirtrider said:

Afternoon Scott

 

 

BMW isn't checking the balance with the drill & tone ring test. They are looking for a very slight acceleration deceleration in the driven tone ring as the spinning U joints work.  That is one reason they spec out a brushless drill as the force driver due to it's very controlled constant RPM. 

 

A shaft U joint failure lock up sure could cause a sudden rear wheel lock up. I think they have had a few reported  on the wethead. 

 

I ride with a rider that had a catastrophic U joint failure on a hexhead 1200 GS a couple of years ago. I was right in front of him doing about 60 mph on fairly straight sandy two track when he suddenly disappeared from my mirrors. I backtracked & found him standing next to his laid over 1200GS. 

 

I asked what happened & he told me that his rear wheel suddenly just locked up (he thought it had a trans issue & was in two gears that the same time). I asked if he was OK & if he went down hard. He told me he didn't go down & rode it out (he is a very good off-road rider). I said why is the bike on it's side, he laughed & said this soft sand won't allow the side stand or center stand to hold it up. There was probably a 200' wiggly line from the locked up rear wheel dragging in the sand. 

 

The scary part was we had just previously entered that two track from a hi-way that we were running close to triple digits.   THAT, would have been a difficult one to just ride out!

 

I won't go into it but recovering that big 1200 GS with a locked up rear wheel was a task to remember as we were a long ways from home & a long way from enough tools to free the locked up shaft then tow it out. 

 

 

 

 

That's scary D.R.  Please school me in this tone ring change in velocity that you mentioned.  It's not related to balance?  What would cause it?

Thx!

Scott

[dirtrider]

1 hour ago, Scotto336 said:

That's scary D.R.  Please school me in this tone ring change in velocity that you mentioned.  It's not related to balance?  What would cause it?

Thx!

Scott

Afternoon Scott

 

That's a darn good question & I would be guessing (somewhat educated guess but still a guess).

 

I really don't see how it could be a vibration thing as I see no accelerometer in the test equipment required. Without an accelerometer of some type there is no way to test for, or record, a mechanical vibration.  

 

They do speak of vibration but my guess is that is a mis-translation from German, probably meaning variation or tone ring changing speed slightly in a rotational type pulsation. This happens a lot when translating automotive related terms by non automotive translators. They translate the word not the meaning. Italian is even worse when it comes to automotive translations, at least from my past experience. 

 

I have been trying to figure this out myself, I have run a number of similar tests in my engineering day job over the years & the first thing that went through my mind was how would (I) test for an impending bad U joint inside a sealed tube.  I have been doing this type of work for about 50 years & I don't have a quick & easy answer. My short answer on this is to just ride it or drive it as I have a pretty sensitive feel for these type of driveline disturbances. But to actually measure or define this with measuring instruments would be difficult without help from our instrumentation department. 

 

I'm not sure if it is looking for (a worn/loose) U joint instant center changing as the shaft rotates so the drag (tone ring slow down speed up) doesn't match a known good profile. 

 

Or if it is looking for a tight then loose spot in the spinning drive shaft plotted against a known good profile.

 

Or it is looking for no tight then loose spot as the U joint rotates against a known good profile.

 

I do know that spinning a vehicle drive shaft by hand I can usually feel a bad U joint so if I can feel it then it can probably be measured then electronically compared to known-good. 

 

But my (guess) is that it is looking for some irregularity in the spin speed plotted against a known good profile. Therefore the specific requirement for only a very few brushless drill types/brands being OK to use to drive it & the suspension held at a precise angle. 

 

Possibly Brad  (Boxflyer) has a more informed answer on this or what they are looking for. 

 

 

 

 

[MichiganBob]

Good Evening all, this is very interesting as I inquired when I was at the dealer last week about the test. The service director could not fully explain it and he said if he could, I might not understand. He said the technician knows when the test fails based on a readout but that was all he could tell me. It must all be above my pay level. 

[RadioFlyer]

Still waiting for someone to request that a dealer test a newly installed shaft and have that request granted.

[RTinNC]

4 hours ago, MichiganBob said:

Good Evening all, this is very interesting as I inquired when I was at the dealer last week about the test. The service director could not fully explain it and he said if he could, I might not understand. He said the technician knows when the test fails based on a readout but that was all he could tell me. It must all be above my pay level. 

[Red]

6 hours ago, MichiganBob said:

Good Evening all, this is very interesting as I inquired when I was at the dealer last week about the test. The service director could not fully explain it and he said if he could, I might not understand. He said the technician knows when the test fails based on a readout but that was all he could tell me. It must all be above my pay level. 

"...based on a readout..." ?  What dat?  I can't believe that BMW engineers have not provide very specific tests, visuals, measurements for determining the status of the drive line.   Doesn't BMW MOA have a customer advocate position on their staff.  If you are a member, maybe a call to MOA if nothing else just to see if they are or have been involved in this saga.

[dirtrider]

5 hours ago, Red said:

"...based on a readout..." ?  What dat?  I can't believe that BMW engineers have not provide very specific tests, visuals, measurements for determining the status of the drive line.   Doesn't BMW MOA have a customer advocate position on their staff.  If you are a member, maybe a call to MOA if nothing else just to see if they are or have been involved in this saga.

Morning Red

 

It's a small scanner type screen that compiles the spinning tone ring input information. (see picture below)

 

BMW probably has a lot of time & testing in that non invasive drive shaft testing equipment. A simple visual won't work as the drive shaft is inside the swing arm. Manual measurements would be very subjective & allow a lot of guessing plus would depend on the talent (or lack there of) of the technician.  

 

A talented tec with a good feel for a good vs bad drive system could possibly catch some but could also miss some that were just starting to fail. 

 

With the BMW testing equipment & readout the little computer can continually be updated as testing many motorcycles shows it strengths or shortcomings. 

 

Depending on the track history of BMW shaft testing system it is probably the best way to catch a failing shaft short of removing it for inspection. 

 

 

 

[dirtrider]

10 hours ago, RadioFlyer said:

Still waiting for someone to request that a dealer test a newly installed shaft and have that request granted.

Morning  RadioFlyer

 

BMW won't test a new shaft (if they know it is new) as the procedure states that a new shaft might not pass until it is broken in. I believe the dealer is supposed to check for shaft history as part of the test.  

 

I'm not sure what would be learned in testing a new shaft as if it doesn't fail (well it is new) and if it fails (well it isn't supposed to pass). 

Added: It seems that we m-i-g-h-t have just learned something? After some time has past I just re-read the last sentence I posted above. (I might not be the brightest light but sometimes even a dim light can find the nut)

 

Due to BMW not testing a new shaft until it is broken in that pretty well points to one of the things (failures) they are testing for is a tight U joint. In a lot of cases a U joint will get tight before failure because of lack of lube, rust in the needle bearings, or severe brinelling.

[Scotto336]

Thanks for your thoughts D.R.  I do have a theory that is not based at all upon any factual knowledge, but that never stops me.  I suspect that fluctuations in rotational velocity in a shaft with u joints could be triggered by both loose/tight/damaged joints and/or being out of balance.  A new shaft could conceivably fail the test if it were sufficiently out of balance, but the test would say nothing about the joints of interest since they are new and not in need of testing or concern.  I don't buy the "needs to be broken in" theory.  In my experience, bearings work fine when new if installed correctly.  I suspect that most shafts are sufficiently in balance such that they wouldn’t cause a balance related failure, at least not in the first x number of miles.  A shaft failing the test at say, 12,000 miles would indicate that either a joint is going bad and/or the shaft has been subjected to a sufficient number of unbalanced rotations to be concerning with regard to bearing damage.  Then again, it could be something else…

[RTinNC]

[dirtrider]

1 hour ago, Scotto336 said:

  In my experience, bearings work fine when new if installed correctly.  

Afternoon Scott

 

Yes, the actual bearings will probably work fine when new but the grease is still packed tight & very stiff plus cap grease seals probably have a lot of drag on them until they are run-in a little bit. I have felt a number of automotive U joints that felt stiff on brand new drive shafts  (CV joints don't have that stiff feel)

 

As far as a balance deal, The BMW test doesn't seem to be looking for that as they aren't using any sort of device to measure balance.

 

Plus that would mean that almost every drive shaft that failed was out of balance for a lot of miles, there are a LOT of BMW riders out there like me that work in a field that deals with drivetrain disturbances. I haven't ridden a lot of wethead bikes but I have ridden enough to say that the ones that I rode didn't have a grossly out of balance drive shaft.  

 

Plus if it was a balance induced failure then why just the rear failing why not some front or both front & rear failing? 

 

I have seen cars & trucks with bent drive shafts buzz so bad at speed they would make your nose itch but still not fail the U joints.  If you spin them fast enough the bend can keep increasing until the shaft explodes but the U joints would hold until shaft failure. 

 

I guess my base thought on it being a balance issue is:   "THAT" is easily fixable at vendor level with a better controlled build procedure or if that can't be easily done then a separate spin/balance test before it enters the parts system. Not even BMW would keep buying out-of-balance shafts (at least I hope not).    

 

So, IF it was balance related, then BMW would have addressed that as soon as it was discovered then motorcycles built from then on would not need 12K checks or 36K replacements & older motorcycles would only need (1) shaft replacement then be good to go life of motorcycle after that. And the 1300 would not have any balance issues (no replacements or checks required)  as those require a new length shaft so new design, new build procedure, new final inspections. Even BMW wouldn't continue to build or use failing out-of-balance shafts once they identified that as the root cause (at least I don't think they are THAT stupid).   

 

BMW could send every new shaft out to a 3rd party testing facility for pre-installation balancing  & still be a LOT cheaper than 12K checks & 3 or 4  36K shaft replacements including labor. 

 

 

[Scotto336]

Well that throws my theory somewhat out of balance .  Perhaps we will never know specifics of the test.  For those less curious I think failure goes back to stress and corrosion and what you can do about it e.g. lube splines, add a vent if not there already and have it tested/ replaced at appropriate intervals.  Oh, and for those with RTs, turn up the radio and ride.      

[dirtrider]

3 hours ago, Scotto336 said:

Well that throws my theory somewhat out of balance .  Perhaps we will never know specifics of the test.  For those less curious I think failure goes back to stress and corrosion and what you can do about it e.g. lube splines, add a vent if not there already and have it tested/ replaced at appropriate intervals.  Oh, and for those with RTs, turn up the radio and ride.      

Afternoon Scott

 

like you, I would sure like to know the exact specifics as well as the root cause or causes & know how BMW plans take this into the future design & hardware wise.

 

There are a number of very smart innovative BMW riders out there that will eventually find lasting work-arounds for this  but first they need to know what problems they need to be solving. 

 

Obviously it is way more complex than as single item failure or it would have been updated by BMW with a one time fix & forget solution.  

 

I think we all have a good idea that a lot of it is moisture (water intrusion) related but that coupled with what (or what's) in addition to the moisture? 

 

BMW does (in my opinion anyhow) use strange dissimilar U joint working angles so possibly that coupled with increased torque of the newer water cooled engines & not enough packaging room for larger U joints m-i-g-h-t be some or most of it (a guess anyhow).

 

I would sure like to instrument the final drive to swing arm to monitor the rear U joint angle to see if it might be operating at or near a 0° angle for extended periods (a 0° working angle is the kiss of death for a U joint). We can look at it statically sitting on it's wheels but we can't tell what's happening under dynamic loading at road speed.  (the pinion gear typically wants to climb the ring gear under power) 

 

 I know there are  (or were anyhow) premium U joints available but possibly not in the sizes that BMW currently uses. 

 

Even the BMW 1200 hexhead bikes had some drive shaft failures, but most were from us 1200GS off road riders that crossed seat deep streams, buried the darn things in mud bogs, climbed hills too steep to walk up at full throttle, & went through full jounce to full extension many times per ride.  (basic rule of off-roading, you beat on it you're going to eventually fail it).

 

I had such a difficult time keeping water & mud out of the swing arm on my old 1200GS that I (& a few others in my area) removed the rear flex boot & rode it with an exposed shaft & exposed U joint. I can't really say if it lengthened the U joint life but it didn't seem to shorten it either. Made it a LOT easier & a lot quicker to re-grease the rear splines anyhow. I was going to drill & put a grease fitting on the rear slip joint but never did (that would have also required a groove cut inside the slip spline all the way around so it would pass grease to all splines), we never had front spline problems.

 

The probable good news is,  that once the failure root (or root's) causes are identified then typically smart BMW riders will find a work around regardless of BMW's lack of interest. 

 

 

[Bluenoser]

2 hours ago, dirtrider said:

Afternoon Scott

 

like you, I would sure like to know the exact specifics as well as the root cause or causes & know how BMW plans take this into the future design & hardware wise.

 

There are a number of very smart innovative BMW riders out there that will eventually find lasting work-arounds for this  but first they need to know what problems they need to be solving. 

 

Obviously it is way more complex than as single item failure or it would have been updated by BMW with a one time fix & forget solution.  

 

I think we all have a good idea that a lot of it is moisture (water intrusion) related but that coupled with what (or what's) in addition to the moisture? 

 

BMW does (in my opinion anyhow) use strange dissimilar U joint working angles so possibly that coupled with increased torque of the newer water cooled engines & not enough packaging room for larger U joints m-i-g-h-t be some or most of it (a guess anyhow).

 

I would sure like to instrument the final drive to swing arm to monitor the rear U joint angle to see if it might be operating at or near a 0° angle for extended periods (a 0° working angle is the kiss of death for a U joint). We can look at it statically sitting on it's wheels but we can't tell what's happening under dynamic loading at road speed.  (the pinion gear typically wants to climb the ring gear under power) 

 

 I know there are  (or were anyhow) premium U joints available but possibly not in the sizes that BMW currently uses. 

 

Even the BMW 1200 hexhead bikes had some drive shaft failures, but most were from us 1200GS off road riders that crossed seat deep streams, buried the darn things in mud bogs, climbed hills too steep to walk up at full throttle, & went through full jounce to full extension many times per ride.  (basic rule of off-roading, you beat on it you're going to eventually fail it).

 

I had such a difficult time keeping water & mud out of the swing arm on my old 1200GS that I (& a few others in my area) removed the rear flex boot & rode it with an exposed shaft & exposed U joint. I can't really say if it lengthened the U joint life but it didn't seem to shorten it either. Made it a LOT easier & a lot quicker to re-grease the rear splines anyhow. I was going to drill & put a grease fitting on the rear slip joint but never did (that would have also required a groove cut inside the slip spline all the way around so it would pass grease to all splines), we never had front spline problems.

 

The probable good news is,  that once the failure root (or root's) causes are identified then typically smart BMW riders will find a work around regardless of BMW's lack of interest. 

 

 

A Thomas Coupling similar to those used on the Bell OH-58 may work at the rear U joint position. It would likely need to be beefier than the one pictured,  also it's a fairly smooth torque load in the OH-58 fitment compared to the BMW.  The BMW has a more abrupt change in torque load in comparison. Thomas Couplings are impervious to moisture, don't need greasing,  tolerate grit but would need cleaning.

 

[dirtrider]

51 minutes ago, Bluenoser said:

A Thomas Coupling similar to those used on the Bell OH-58 may work at the rear U joint position. It would likely need to be beefier than the one pictured,  also it's a fairly smooth torque load in the OH-58 fitment compared to the BMW.  The BMW has a more abrupt change in torque load in comparison. Thomas Couplings are impervious to moisture, don't need greasing,  tolerate grit but would need cleaning.

 

Evening  Bluenoser

 

A number of auto companies used to use that type of a coupler in the steering shafts. They had limiting pins to prevent over flexing the joint & provide a safety if the rubber/fabric fails. 

 

I'm not sure what the max working angle that type of joint can handle as they are made more for minor angular offsets. 

 

You can't make those too thick or they won't have much of any angular ability, so to handle the torque the diameter would probably have to increase. It would become very difficult to package inside a flex boot.

 

It's definitely a cheap option if it could be packaged in the limited space & still be made robust enough to handle the torque. That would be tough nut to crack.

 

 

[Bluenoser]

57 minutes ago, dirtrider said:

Evening  Bluenoser

 

A number of auto companies used to use that type of a coupler in the steering shafts. They had limiting pins to prevent over flexing the joint & provide a safety if the rubber/fabric fails. 

 

I'm not sure what the max working angle that type of joint can handle as they are made more for minor angular offsets. 

 

You can't make those too thick or they won't have much of any angular ability, so to handle the torque the diameter would probably have to increase. It would become very difficult to package inside a flex boot.

 

It's definitely a cheap option if it could be packaged in the limited space & still be made robust enough to handle the torque. That would be tough nut to crack.

 

 

Evening Dirtrider,

The Thomas Couplings used by Bell have multiple metal disc's, 10 or so, stainless steel I believe. They're used where the angle is very near zero. 

[LAF]

And the mention of 1300 DS made me think that I read they are longer now.  I believe it is from moving the transmission to below the motor. 

 

So I wonder what that adds to the equation?   I would think less degree of the shaft itself.

 

I would think BMW does not want to go through this again. Not cheap, and we feel the end result in higher prices.

[dirtrider]

13 hours ago, LAF said:

And the mention of 1300 DS made me think that I read they are longer now.  I believe it is from moving the transmission to below the motor. 

 

So I wonder what that adds to the equation?   I would think less degree of the shaft itself.

 

I would think BMW does not want to go through this again. Not cheap, and we feel the end result in higher prices.

Morning Lee

 

Good point_

 

I also heard they lowered the transmission. 

 

This "could" lower the output shaft therefore decreasing the front U joint angle. BUT, to keep the drive shaft from having a lot of plunge during suspension movement  (therefore needing a slip yoke on a longer spline, or requiring a mid shaft slip spline) they would probably need to keep the front U joint center aligned with the swing arm front pivots. THIS, would require a complete rear suspension re-design.

 

To avoid the suspension re-design the easy way would be to lower the transmission but flip the gear shafts around so the output shaft exits the transmission in about the same place as it does now. 

 

As of now I haven't paid much attention to this so it something we need to figure out.

 

Not that this is the actual parts but a quick look at the 1300 parts book shows the final drive with about the same length spline  (so not much length for added plunge length there), still shows a font snap ring (so that is locked in place with no plunge).

 

The shaft picture shows a 2 piece shaft (looks like rubber cushioned), I can't tell if it has a center sliding spline. Doesn't really look like it but it could have one that isn't obvious. Interesting as the picture still shows a shaft with non-matching front & rear U joint clocking.

 

It could be just a generic picture or possibly they don't care about the U joint alignment, or they have it mis-clocked for a specific reason. (I have seen on-purpose non-alignment clocking in the auto industry to address a vibration issue but the clocking is usually only off one spline tooth)

 

If BMW is using a near 0° rear U joint angle with a higher angle in the front then U joint clocking would not really matter as a 0° working angle can't cancel the front working angle no matter what clocking. Ideally you want matching front & rear working angles so the proper U joint clocking allows one to cancel the other.  

 

Interesting, glad you brought it up__

 

Added later:  I dug around on the Internet a bit & it looks like on the 1300 the transmission output shaft is the highest shaft & even an orphan. I can't really make a comparison to the 1250 but it looks high enough to be close anyhow. The 2 piece drive shaft looks to have a rubber cushion but I didn't see a sliding spline joint so the front U joint center is probably still on the swing arm pivot centerline. 

 

 

[Mellow]

Interesting, I wonder if the low-suspension GSAs are less likely to have a u-joint failure vs standard suspension...

[dirtrider]

2 minutes ago, Mellow said:

Interesting, I wonder if the low-suspension GSAs are less likely to have a u-joint failure vs standard suspension...

Morning Mellow

 

Possibly as I "think" they now require a 50K replacement interval rather than a 36K replacement interval. But this could just be because on the 1300 I believe the customer pays for the shaft replacement (a $1300.00 shaft plus labor) at every 36K just might turn costumers away.    

[Mellow]

2 minutes ago, dirtrider said:

Morning Mellow

 

Possibly as I "think" they now require a 50K replacement interval rather than a 36K replacement interval. But this could just be because on the 1300 I believe the customer pays for the shaft replacement (a $1300.00 shaft plus labor) at every 36K just might turn costumers away.    

Morning.... Sorry, I'm talking about the 1250s...

 

Too bad we don't have any statistics on the bikes that have had failures, replacements... that would be interesting.

[RTinNC]

16 minutes ago, dirtrider said:

Morning Mellow

 

Possibly as I "think" they now require a 50K replacement interval rather than a 36K replacement interval. But this could just be because on the 1300 I believe the customer pays for the shaft replacement (a $1300.00 shaft plus labor) at every 36K just might turn costumers away.    

I thought the shaft price has been reduced to less than $300.   Still not something I want to sign up for but much better than the original BMW price. 

[dirtrider]

17 minutes ago, RTinNC said:

I thought the shaft price has been reduced to less than $300.   Still not something I want to sign up for but much better than the original BMW price. 

Morning RTinNC

 

Unless BMW has a special price for owners of the 1300 at mandatory replacement then the parts book shows the 1300GS shaft is    (take a deep breath)      $1,570.66 + tax & labor obviously.

 

I guess that is one sly way of getting BMW owners to trade-in their motorcycle at 49-50K & buy a new one.  

[dirtrider]

57 minutes ago, Mellow said:

Morning.... Sorry, I'm talking about the 1250s...

 

Too bad we don't have any statistics on the bikes that have had failures, replacements... that would be interesting.

Morning Mellow

 

On the lowed 1250 it's anyone's guess, it could help or could hurt, we are still not sure on what all the failure factors are (we are pretty sure moisture is one factor). A lowered suspension would definitely decrease the front U joint running angle but with the way the rear link & drive pivot are offset it could hurt (or could help) the rear joint  angle.

 

As far as "statistics on the bikes that have had failures". I'm sure that BMW have been tracking this as best they can but unless all the shafts were returned to BMW for failure analyses (I'm pretty sure that was a requirement to begin with) it was probably only tracked with shaft failure analyses until they had a good handle on what was happening, from then on they probably tracked the failure vs milage as well as state or region that it the motorcycle was repaired in (or possibly owners home address).

 

I'm pretty sure BMW would have a tracking system that looks at multiple things like (was it an actual shaft failure) or (just beginning to fail so it flunked the drill drive spin test), or (was it a 36K replacement that was failing) or (about to fail) or (still good),  etc.

 

BMW will never release the tracking data without a court order & even then they might have  (probably do have) their tracking set up to eliminate certain key words like  (total failure), (lock-up),  (drive disconnection), you get the idea.

 

Kind of like a vehicle fire, most auto companies avoid the word fire & refer to it as thermal incident, or a stuck throttle as a throttle event, or sluggish throttle. 

[Bruno From Québec]

On 7/7/2024 at 12:49 PM, Rob Nowell said:

If they're willing to do it for free, ...why?  But that's just me.

Because they always put the tupperware screws back in the wrong holes