BMW K75 K100 Final Drive Driveshaft Spline Failure Causes

Reasons why BMW has such a high driveline or driveshaft failure rate compared other motorcycles brands. Compares and contrasts the non-bmw approach to drive shafts and why they are so much more reliable. Asks the question: what advantage is there to a dry clutch? Looks at repair options, re-spline costs at Hansen's BMW.

[@itshildo]

Thanks for the clear explanation. I have a 1994 K1100LT and had it lubricated, this makes riding with a driveshaft expensive. Nobody would want a car that would require pulling the driveshaft for lubrication every 15000km or so... I agree with your that BMW has made a series of major design flaws in the final drive system. What I cannot understand that a respectable company as BMW has continued with this system for so many years, and customers let them get away with it. Very strange.

[@ChrisR.Harris]

The pinion splines of the bevel drive / driveshaft rear tube portion are to be CLEANED and lubricated with either a moly-based grease or the proper Staburags NBU30PTM every time the rear tire is replaced (8,000 miles). Failure to do so will result in spline failure at the back usually around 40,000 - 50,000 miles. Proper repair performed by Bruno’s Machine & Repair consists of the driveshaft tube being resplined and plugged to retain grease and the pinion splines rebuilt and made 13 mm longer.

[@lodgeblog]

Very clear and concise exposition of how the K series transmission works, its design weaknesses and why lubing the final drive shaft splines is necessary. I have had my K75S 26 years and I've never done this but the bike is still pretty low mileage. However, after viewing this vid I'm definitely going to lube those splines! Thanks for sharing this.

[@stevensapyak7971]

I like your method of recording the date,mileage,& Moly 60, on the transmission case! Slick.

[@ChrisR.Harris]

The transmissions input shaft splines / clutch friction disc splines are to be cleaned and lubricated every 20,000 miles on Airhead and 2 valve K's. All Paralever models including Oilheads are to have this done every 40,000 miles. This requires removing the transmission. BMW stopped listing spline lubes in the 1990's likely due to the ridicule they received by the motorcycle press regarding these outrageous service intervals. Any experienced BMW tech should know this and now you do as well :)

[@pcofranc]

Good, I loved my bike too. Remember, this is not an attack on the brand. New models are being changed and improved but owners of the k75 need to know three things about the k75s drive system: 1. it is very strong (it is the same shaft used on powerful k1100) 2. it needs good quality grease to keep it in good working order 3. If it is taken care of it will probably last 150K miles or more. Follow this program and it will not fail. If you shaft is worn this video shows you how to fix it.

[@pcofranc]

Marketing and advertising and the BMW brand are well known. BMW specializes in the touring segment of motorcycle riding for middle aged men. BMW owners typically has a lot of disposable income and believes in "regular maintenance" - like owning a "weekend-only". Owners like myself are looking for utility and reliability. I liked the K75 because it was lighter 500 vs 700 lbs than the Honda st1100 /1300 and got better gas mileage 32 vs 40-45mpg.

[@pcofranc]

@videoheadnow Thanks. I'm not trashing the design just comparing and contrasting - just food for thought.

[@swordfish778]

Thanks a lot for this explanation on my K75 failure. For me it came out of the blue. Without warning standing in queue 1:st gear in releasing the clutch a high sound of something breaking in the transmission and the failure was a fact.

[@stevensapyak7971]

The Softails had belts manufactured by Gates. They are IMO the best system for,cost,maintenance,& fuel efficiancy.

[@pcofranc]

@videoheadnow - Yes, after the spine failures - in some ways the old chain never looked so good. Check out the Buddy Oiler? It is a constant oiling system and extends chain life to 50K miles or more so does enclosing the chain in a protective cover to keep dirt out and lube on. Hope you are enjoying the F650 - I had it as a loaner one time and I think it is a great bike with plenty of power and great mpg.

[@stevensapyak7971]

Good essay. The Yamaha XS750 had its drive line system designed by Getrag AG. In Germany. I owned Harley Softails and they were easy to adjust & maintain.

[@pcofranc]

@DGillyy Without spending hundreds of dollars on special purpose grease, Moly 60 is probably the best grease for splines ($15 3oz 2007 prices). BMW, makes a high quality grease which costs around $15 for 3 oz. The dirty secret is that BMW and Honda and most dealers use the cheapest grease available. Dealer replaced my clutch in 2002, 4 yrs later spline was bone dry, rusted. Shifting was smooth for 3 years (15K mi). When I used Moly 60, 3 years later bike shifted like silk.

[@pcofranc]

My dealer stated that BMW does not offer an interval for greasing the splines. My owners manual does not list this either. Can you provide picture of any documentation from BMW that states the interval for this procedure?

[@Paulkay211]

Thanks ... best explanation ever !!

[@pcofranc]

You're welcome and you know what I owened That bike I Is determined to find the route cause.

[@nobodyyouknow222]

The rubber shock coupling in the middle of my K-100RS( 4 valve) failed before 10K miles... this is simply a shoddy part.. and not maintenance related ( although the 2 young guys before me might easily have been stupid ! ) So on this I will agree.. crummy part. Worse, the dealer was so lame they couldn't do a proper compression test... and told the P.O. that bike needed a valve job. I bought it because it ran like a watch, and clearly did NOT have any compression/engine problems ! In went the new drive shaft, and I drove away happy. Vroom Vroom.

[@camel747]

What blows my mind even further, is that with the 16 valve series, they went for an additional joint in the drive shaft, negating any unwanted up and down action (which never ever bothered me) of the rear wheel while accelerating and braking. It introduces two extra bearings and a rubber boot to worry about. The ultimate irony is that the scott oiler assisted chain of my brother's VFR actually needs less attention and is way cheaper to maintain than my fancy 'worry free' drive shaft.

[@pcofranc]

My dealer stated that BMW does not offer an interval for greasing the splines. Can you provide picture of any documentation from BMW that states the interval for this procedure?

[@pcofranc]

I LOVE never seize (a mix of graphite powder and oil). My answere is no. Never seize / Anti-Seize works best on parts that don't or rarely move like bolt threads and lug nuts on a car. Or the spline on the bmw k75 rear wheel - not the drive shaft but the spline that the rear wheel slides on to. I have found in wheel bearings or other parts that move a lot and fast it does not provide good lubrication the way engine oil, gear oil or grease does.

[@pcofranc]

Ouch, did you replace it? If so pleas post updates. Thanks.

[@pcofranc]

@itshildo I think it shows the power of marketing! Bmw is finally switching to a sealed unit that needs no maintenance. However, they are having problems with the bearings and final drive unit separating. Hopefully, they will get it together as the bikes are practical and comfortable and unique.

[@harrieke61]

@pcofranc My bike uses the original shaft that was mounted in the factory more then 20 years ago. The mileage (in my case Kilometres) gauges is showing 242000KM. The original clutch is replaced at 220.000 Kilometres. after lubrication the outputshaft with staburag and fitting a new plate and oilseal at the output shaft all is OK again

[@harrieke61]

@pcofranc, In answer on your question about how many driveshaft i have had replaced, the answer is none, I still use the same shaft that was placed by BMW at production, my K100RT is one of the last production day of this type as confirmed by BMW itself (framenumber 97823). It has >230000KM on the odometer and with every tyre change i also grease the splines, it takes my about an hour to do this, I use my K100 daily for worktravel and outings and use 2 sets of tires on 40000KM a year.

[@jamesbroughton]

Last week my final drive bearing went after 38,000 miles on my r1100rt. It dislodged the seal and gear oil leaked all over the back wheel. Is there a design flaw here too? I know the R1200 models have a hole in their final drives and use needle bearings instead. Has this solved the problem of final bearing failure? Thanks

[@pcofranc]

@harrieke61 I agree - as I state In my spline lube video series - if the spline is lubed with good grease it will likely last well over 100K miles.

[@83226505]

The majority of problems are caused by people not using the correct spline lube.....and....failing to lube the splines at correct servicing intervals. Constantly people are saying they know best about when and what to use to lube their splines. Well guess what, they are wrong. Every service the splines need to be cleaned and re-lubed with the correct spline lube.

[@pcofranc]

Unfortunately BMW setup very poor example by using very cheap grease that dries out rock hard I think the best grease to use is anything with a high Molly content 60%

[@shiza237]

I was wondering, wouldn't an aplication of'' never cease'', actually address this issue? I've been asking on forums , but no one seems too know, or care. What do you think??

[@pcofranc]

@camel747 I met a guy that had 40K on his chain and sprockets because he used the buddy oiler. Also, the early 1980's virago offered an enclosed drive chain which the manual suggests should last at least 38K! It not only keeps the chain lubed but keeps dirt away from it.

[@pcofranc]

You are welcome.

[@harrieke61]

@pcofranc In answer to your question of how many shaft replacements i had, the answer is NONE. I still drive with my first driveshaft. The problem is poor maintenance not a design flaw

[@danbromberg]

Any videos available for a K75S (engine) oil change (especially showing the 'belly-pan' removal) ? Thnx, Dan

[@pcofranc]

Dan Bromberg Probably / possibly buried in my k75 video collection. I removed it once maybe to reseal it and as will most procedures there are things that are helpful to know before doing it.

[@pcofranc]

lol! Thanks for the humor!!!!!!! I loved it!!!!

[@pcofranc]

I don't know about this model so I can really speak to that problem. It does not sound like a design flaw to me. Remember, if a seal is not put in correctly at the factory or is compromised during wheel removal for tire changes (I don't know if that is possible for your bike) then a leak can develop which is not the seals fault. You would need to gather information on how often this happens and at what mileage and other info like how hard the bike is ridden, hot / cold climate etc. Good luck

[@isbemorph]

i wonder how would it compare to a moto guzzi setup which also has a dry clutch and longitudinal engine. And why such failures dont happen to cars, nobody lubes front driveshafts which have splines on both ends and basically they are installed dry.

[@pcofranc]

that's a very good suggestion about comparing to Moto Guzzi I did not realize that they also use a dry set up. Now comparing this setup to a car there are some important differences the rear differential is sitting in oil the only part that turns is the universal which does where out and can be replaced and in modern vehicles the universal itself has been replaced with a different type of joint. Regarding the front clutch splines remember that on the BMW little or nowhere takes place even when the grease is completely dry however it does cause a problem with shifting and in that case I'm not sure why cars which use the same basic setup do not suffer from the same problem it could be that the transmission has synchros versus the constant mesh transmission that motorcycles use.

[@pcofranc]

Correct, the design requires lubrication - however, BMW did not include this procedure in the maintenance schedule. It can happen at low miles as the bike ages and the grease dries up. Many owners learn after a costly drive failures that an informal "schedule" was developed. Shafts in all other bikes are tried and true technology that offer almost no maintenance. I have yet to see an explanation for the benefit of the BMW dry design? Even BMW has abandoned this design.

[@pcofranc]

@videoheadnow Use mileage as the guide. If the bike has under 10K miles even if it was never lubed it should be fine if you clean and lube it as soon as you get it. If the bike had 20K + then you want see if the seller has maintenance records and put the bike on the center stand and rock the rear tire back and forth with the motor off and bike in gear to assess the degree of wear (without dissembling and inspection).

[@almccallie4314]

how often / miles should I grease my final drive? 1993 K75 RT. Maintenance records indicate it was greased in 2002 at 23,000 miles. Now in 2023 it has 27,000 on it. Its only 4,000 miles but many years since service. Advice appreciated. Thank you.

[@pcofranc]

I would absolutely remove the final drive to inspect and clean the existing grease and replace that with 60% Molly grease and take pictures that you could show to a future buyer to prove that it’s in good condition. Even though the miles are low there’s a danger if cheap Greece was used or it wasn’t done properly and it’s not worth taking a chance and remember you don’t have to do the clutch blinds because they never wear out even if they’re completely dry. It’s only the final drive that’s in danger. Unfortunately it takes less than an hour and a half to remove it clean it and grease it and put it back on.

[@almccallie4314]

@@pcofranc Paul, BIG THANK YOU for your reply. I inherited the bike from a friend who passed away who had over a million miles logged on motorcycles. I’m trying to learn all I can about it. It is in showroom condition and runs / rides excellent. I’ll hopefully keep it for the rest of my life. I really appreciate your help. Al McCallie Cody, WY

[@pcofranc]

@swordfish778 When something breaks - I say: "my someday is today". I hope you have your machine up and working good!

[@donnlarossa9173]

My u joint broke at 70 k. Guess that's normal it's a 89 k 100 rs Total bill was $625.00 at Lior motor ride in Corona Cal GREAT JOB!

[@pcofranc]

Donn La Rossa that's not bad I would say that you joined could probably last longer but it all depends on lubrication and how was driven in that kind of thing you know by the time we get to 90,000 miles plus many years old things happen

[@donnlarossa9173]

I sold this bike and got it back for free 2 yrs later with Satan Stickers all over it and bird shit! lol I went thru everything and put a used trans in it and 6k later and bingo it's back! lol I even had my Priest bless me on it! I also installed a magnum fuel chip that gave me better mileage and more torque and HP! I have a Flying Brick BMW K Bike Club of Southern California you are welcome you like GREAT VIDEO PAUL! I had many problems like the gas tank pressure and handling i have worked out now. Heading out for a trip soon. I also have a new BMW 122 R/S and a BMW 1982 100 R/S I have had up to 5 at once but nearing 70 now lol Thank you for reply looking forward to more conversations. There are many question I still have lol >> facebook.com/The-Flying-Brick-BMW-K-Bike-Club-SCal-874994812609511/

[@pcofranc]

@harrieke61 My conclusion has nothing to do with my choice of grease. The video compares bmw's design which has an extremely high failure rate of drive shafts to the design EVERY other manfacturer uses. My friends 1993 virago now has 80K miles on it and the shave has NEVER been services. This summer the rear shaft / final drive finally failed and was replace. How my times has your shaft been replaced?

[@camel747]

@pcofranc That's it. I'm installing chain drive on my car too:)

[@nobodyyouknow222]

Paul, Your K-75 and Mine are at least 19 and perhaps as much as 26 years old. The lubrication interval needs to be observed. Your bike might only have 35K miles.. but it is long long overdue for spline lube. The Honda Moly ( molybdenum) spline lube product is so superior to the BMW label goop... that beemer dealers routinely use it ! The "bitch" isn't the dry clutch automotive type drive-line... but rather the crummy lube that was used during manufacture.. and perhaps subsequent maintenance. You are clearly smart enough to have done your own clutch replacement. "Misalignment" is pretty darn hard to achieve between the clutch and transmission. Now, if you don't happen to like the dry clutch, separate transmission architecture.. why not buy a similar Honda or Kawasaki.? The used K-75 represents one of the finest used motorcycle values available. They are capable of 300K mi endurance. During the 50 years this is likely to happen.. stuff is going to fail strictly from age, and more from deferred maintence ( by previous owners). Once sorted, these bikes repay you with economy, safety, and comfort. The K-75 is reasonably sporty, and over the long haul reasonably comfortable. All machines have their strong and their weak points, both in terms of failures, and repairability. Relative simplicity, low parts count, and field serviceability with hand tools is the strong suit here. too expensive new, but great bargains used... with the caveat that doing your own work is the key to making financial sense out of owning a BMW. Post K-1100... I wouldn't touch one. too complex, too big, too prone to failure. But your K-75. One of the real successes of BMW after the R-75/80.

[@pcofranc]

Capt Larry Well said. Long live the K75's and k100's. I sold mine in 2009 and in 2011 I got a Kymco Grandvista 250cc scooter. Scooters in general, are the ultimate in simplicity and reliability and clean with an enclosed engine.

[@raybrensike42]

Lately BMW has been designing unreliability in the drive system, hoping you will buy a new one. They don't like me so much. I've been doing my spline lubes and been keeping my going.

[@mitreswell]

I'm very disappointed with the BMW engineers. What were they thinking? So much for German engineering excellence . . . Doesn't appear to have been designed to last without some fairly invasive and expensive maintenance. Lubing the clutch drive is a major undertaking, which I'll get round to one day.

[@pcofranc]

I totally agree part of the problem is that the internet created this myth that the k bikes were the greatest thing ever invented and would last forever and they probably could with proper maintenance but there's a lot of strange things in the design which basically build in maintenance for the dealer and that takes away from the ownership experience especially as the bike gets older. My friend bought a 2004 k1200 LT and when the clutch went out it was over $4,300 at the dealer to have it replaced that was on top of spending at least $3,000 have brake lines replaced and a few other issues. In one year he's into that bike for about $12K. My current ride I've owned for 2 years it's a 2012 Honda NC700X and while it's not perfect the thing is mostly bulletproof. I was so away on a trip for 2 months when I started the bike it started instantly The battery wasn't low and it was like it had just been running.

[@Master-di4di]

Germans are a bit like poms.They don't like changes.Stupid engineering putting spline outside lubrication sources.Next bike will be a wet clutch & drive spline. Great video.

[@pcofranc]

@slipperyox lol - I'm still kicking (alive) but I am in hiding from BMW hitmen! ;-)

[@hansworst7170]

wet clutch are crap they will burn much faster when mis threaded

[@jwcarreira]

ive had no problem and i beat the shit out of it ! i love all bmw's

[@jeroenoost6217]

Yep, but just apply staburag grease every 40.000k and you drive a K75 easy 300K without problems..

[@almccallie4314]

Do you think it’s mainly the rear splines at the final drive or should the clutch / front splines require maintenance also?

[@jeroenoost6217]

@@almccallie4314 it is not such a big job all together, so I would advise to do grease both splines in one go

[@almccallie4314]

@@jeroenoost6217 Jerome, thank you for this information. It is really important to me and a big part of my motorcycling experience. As for greasing the front end of the driveshaft…does it come out easily? Any tips on how to break it loose? I really appreciate. Thank you.

[@almccallie4314]

@jeroenoost6217 I did it. Upon discovery not much grease left but all surfaces were in good to excellent condition. Applied Staburags liberally to front and rear driveshaft splines. Documented before and after with photos for potential buyer. Thank you for direction and advice. Al McCallie Cody, Wyoming

[@pcofranc]

@camel747 Yes the Scott Oiler - I couldn't remember the name. I think the problem is always the fat guy in marketing - he wonders over to the engineers at bmw and asks for some new thing that he can use in advertising brochures. It is true that shaft-jack can be considerable - esp on the old honda magna 750 /1100. Especially at high rpm's. But I agree if you are having problems with the basic shaft why add another joint and bearings.

[@nobodyyouknow222]

New driveshaft is worth the money, while available. No grease fittings.. dumb. Paralever ( on K-100) isn't going to fly without the rear spline being outside the bevel gear assy. Is paralever worth the trouble ? Nope.

[@pcofranc]

Capt Larry I suppose a hole could be drilled and grease fitting installed. New shafts are a must while available.

[@TheClaesGoran]

I had the same problem with my K75. I will try to make a survey to find out how common spline and clutch problem are with BMW MC's. If you want to participate please contact me on [e-mail] regardless of whether you experience any problem or not, and I will mail you some questions. Remember that every vendor denies any problem as long as possible until a magazine or TV programs bring up the issue.

[@harrieke61]

your conclusions does not make any sense at all. BMW states in their maintenance schedule that the splines at the end of the driveshaft MUST be greased every 30000KM's with a special kind of high sticking grease called Staburag. I drive a K100RT with 230000KM on the odometer, and thanks to regular lubing of the splines I do not have the this kind of trouble. I drive my bike every day for work.

[@almccallie4314]

Do you lube both front and rear splines, or should I only be concerned about the rear (final drive) splines?

[@hansworst7170]

no problems with japanese bikes is bullshit, most bmw are old too.....