K1200S transmission failure - K-Bikes.com - Excellence in Motion
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post #1 of 82 (permalink) Old Oct 17th, 2006, 4:18 pm Thread Starter
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K1200S transmission failure

My 2006 K1200S, mfg date 01/06, has had a transmission failure. Current mileage: 8,100 miles. Problem began at about 7,900 mi. Symptom: momentary total power loss (about 1/4 sec), only at near-full throttle, and ONLY in 2nd gear above 8,000 rpm. Felt almost like a misfire, or briefly hitting rev limiter, only more harsh. No rpm spike or audible grinding sound. No ECU codes set.

Once problem began, behavior was 100% reproducible and consistent under the stated conditions. It wasn't intermittent.

Transmission teardown in progress by dealer, but gear damage and bent shifter fork is already obvious.

Behavior happened within 100 mi of installing full Akropovic exhaust and EVO intakes, so of course everybody at first suspected that (before damage area was isolated).

BMW now agrees the mods had no effect, and problem shouldn't happen even during extremely aggressive riding.

Bike purchased new and always maintained by dealer. I ride it sportily but never do clutchless shifts or speed shifts. Never been wrecked.

They'll continue the teardown, replace/repair the transmission, send oil analysis out. If BMW Motorrad requests, they'll ship the damaged parts/tranny to Germany for forensic analysis. Obvious question is whether cause is defective components (metallurgy, etc) or an assembly problem during manufacturing.

Just a total mystery at this point.

Has anybody else heard of K1200S or R transmission failures?
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post #2 of 82 (permalink) Old Oct 17th, 2006, 4:48 pm
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I find it hard to beleive its your tranny with intermitent power loss at full throttle . If second gear broke there would be no gear in second period . As you can see the drum holds the shifter forks in place so they can't move from their programed position, it would not come and go. They usually also make a terrible noise when they let loose. The only other thing I can think of is missing teeth or melted teeth if it was the tranny but it would still make a hell of a racket IMHO
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post #3 of 82 (permalink) Old Oct 17th, 2006, 5:50 pm Thread Starter
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Quote:
Originally Posted by tonysrep
I find it hard to beleive its your tranny with intermitent power loss at full throttle . If second gear broke there would be no gear in second period . As you can see the drum holds the shifter forks in place so they can't move from their programed position, it would not come and go. They usually also make a terrible noise when they let loose. The only other thing I can think of is missing teeth or melted teeth if it was the tranny but it would still make a hell of a racket IMHO
Tony, several VERY experienced technicians had exactly the same thoughts as you posted. The failure symptoms seem atypical for a transmission or gear failure. Also reproduced it on a dyno, where wind noise isn't an issue. Still couldn't hear grinding, but putting hand on transmission case during the problem indicated possible mechanical issue, sort of a "chunk" vibration.

Just to be clear: problem isn't intermittent in the sense of hard to reproduce -- it happens every single time those exact conditions are met: 2nd gear, high power, above about 8,000 rpm. Never, ever in any other gear. Power interruption is momentary (about 1/4 sec) but physically violent -- entire bike shakes from power disruption. Yet no audible grinding or high rpm as if slipping out of gear.

If you pin the throttle in 2nd, it always happens at least once between 8k and redline, sometimes 2-3 times. If you stay on the throttle (which takes some guts under those conditions), it pulls to redline.

At dealer's request, we tried many things to better understand problem, inc'l continuously applying shift pressure on shifter after reaching 2nd gear, put stock intake back on, etc. This resulted in many runs to reproduce the problem.

Toward the end of that day, problem seemed to be progressively getting worse, on the last run it happened at about 6k rpm at about 2/3 throttle. In hindsight, we were probably further damaging the transmission with each pass, but symptoms were so puzzling we (inc'l BMW) were unsure it was transmission, ignition, fueling, throttle butterflies, or something else.

Thanks for posting that picture. I'm going to the dealer to inspect the teardown tomorrow. Maybe I could take some comparative pictures.
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post #4 of 82 (permalink) Old Oct 17th, 2006, 9:29 pm
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If this were a car (thats what I mostly repair). I would be watching the crank and cam sensors with a scope at test speed checking to see if there is a brakedown in the pulse from the sensor. I have also seen ignition switches cause the same problem The contacts usually used are copper ,they deform and corode with the heat generated in the contacts. Is their an alarm system on the bike? If so I would check it also.

The chunk they feel might just be the gear lash between the clutch basket and the crank caused by the shutdown. There is also a large lash between the syncro cogs on the gears themself's. (I think)

Last edited by tonysrep; Oct 17th, 2006 at 9:35 pm.
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post #5 of 82 (permalink) Old Oct 18th, 2006, 4:05 am
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Odd behaviour for a transmission failure. If you start from the final drive and work along the drive assembly, the final drive is common so if it works in one gear throughout the power / torque range then the final drive should be ok.

Odd that there isn't the usual accompaniment of expensive grinding howling noises coming from the gearbox if there are loose bits floating around inside.

Isn't there a gear sensor that picks up the individual gear the bike is in at any time. If the fault is present in specific gears only then perhaps the ECU is getting incorrect input on gear selection either on an intermittent or periodic basis.

Please keep us posted on progress.
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post #6 of 82 (permalink) Old Oct 18th, 2006, 6:04 am
 
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I have a problem that shows up, then goes away and can not reproduce at will. The problem is hitting a false neutral between 5th and 6th, upshifting and/or downshifting. It mostly occurrs shifting around 110- 120, but has happened at 90 MPH. The bike was placed in the shop several times, techs take it for a test ride, and it does not happen with them. I really wonder if they are in the low triple digits when trying to catch this ghostly issue. Frequency of issue, well it can happen three or four times within 200 miles, then go 1500 miles without any issue, then hello back again. I've noticed that I'm in a left moderate lean angle (90+% of the time) when it occurs. It does make grinding noises, as if the teeth of one gear are clipping the teeth of another gear. Several times at the beginning of the problem, the rear tire tried to lockup. It takes a good effort to shift back into 5th or into 6th. The clutch lever is hard to pull in, when compared to the normal operation of it. Also, the gear illumination panel is blank, no 5 or 6 indicated until I get it back into a gear. I now have 10300 miles on the bike and this problem has occurred 11 times. Tryed many times to duplicate the problem, but there is no way to hit a neutral between 5th and 6th, until the problem occurs. BMW NA will not autherize the dealer to inspect the problem. BMW NA thinks it's the rider and not the bike. I now carry a tow company's card in my pocket so the next time it happens, I can stop on the side of the road and call a roll back.

Please post when your problem is resolved.
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post #7 of 82 (permalink) Old Oct 18th, 2006, 8:43 am
 
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Quote:
Originally Posted by joema
My 2006 K1200S, mfg date 01/06, has had a transmission failure. Current mileage: 8,100 miles. Problem began at about 7,900 mi. Symptom: momentary total power loss (about 1/4 sec), only at near-full throttle, and ONLY in 2nd gear above 8,000 rpm. Felt almost like a misfire, or briefly hitting rev limiter, only more harsh. No rpm spike or audible grinding sound. No ECU codes set.

Once problem began, behavior was 100% reproducible and consistent under the stated conditions. It wasn't intermittent.

Transmission teardown in progress by dealer, but gear damage and bent shifter fork is already obvious.

Behavior happened within 100 mi of installing full Akropovic exhaust and EVO intakes, so of course everybody at first suspected that (before damage area was isolated).

BMW now agrees the mods had no effect, and problem shouldn't happen even during extremely aggressive riding.

Bike purchased new and always maintained by dealer. I ride it sportily but never do clutchless shifts or speed shifts. Never been wrecked.

They'll continue the teardown, replace/repair the transmission, send oil analysis out. If BMW Motorrad requests, they'll ship the damaged parts/tranny to Germany for forensic analysis. Obvious question is whether cause is defective components (metallurgy, etc) or an assembly problem during manufacturing.

Just a total mystery at this point.

Has anybody else heard of K1200S or R transmission failures?
I have also had the same exact problem as well as some other members. Follow link.

http://www.k-bikes.com/forums/showthread.php?t=5921
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post #8 of 82 (permalink) Old Oct 18th, 2006, 11:30 am
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Well dude,

Bad news. THOSE SYMPTOMS ARE IDENTICAL TO MINE!!

Its not really the second gear itself that's the problem. Its the Shift fork. You'll be getting a new transmission and don't hold your breath cause it won't get done quickly. You'll be without a bike for a month. Raise hell if you know how cause they gave me a new 3-series BMW to drive around while they had mine.

You've already read my post I see. My service was done at Long Beach BMW (CA) and the service advisers are Bruce and Natalie. They'll be happy to talk to you about it I am sure as they ended up eating the cost of the car.

Good luck. I am sure everyone will eventually have this issue and there will be a very large recall which will suck for all.


T

Now you see me, now you don't
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post #9 of 82 (permalink) Old Oct 18th, 2006, 2:42 pm
 
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The dealer that handled my tranny problems.

BMW of Manhattan Motorcycles
555 West 57th Street (at 11th Avenue)
In the BMW Building
New York NY 10019
Phone: (212) 373-7863 Fax: (212) 314-9764

Total time was only two weeks.

My Name is Justin Zaleski
vin# WB105940X6ZN56009
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post #10 of 82 (permalink) Old Oct 18th, 2006, 5:47 pm Thread Starter
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Examined my dissembled transmission at dealer. Obvious damage to 2nd gear shift dogs (the pegs that extend sideways from the gears) -- edges brutally rounded off. The dog housing into which they slide was scuffed, and the dog slots were likewise damaged. Gear faces themselves looked OK. No obvious clutch damage.

One face of a shifter fork was very damaged -- scuffed and abraded, looked almost burned. Forks themselves weren't visually bent. The shaft on which the forks slide might have been bent -- the forks would slightly bind at one point when sliding them back and forth on the shaft.

Apparently under high loads in 2nd gear the dogs would slip out of the dog slots, rotate at least 45 deg, then brutally slip back in, restoring power. I can't believe the entire transmission didn't explode under that load !!!

The big question: which of that damage is the result of failure propagation, vs which (if any) was the initial root cause. More importently, what exactly was the root cause? Was it a component failure or was it mis-assembled somehow? Maybe insufficient design margins on one of the components?

The entire transmission will be replaced with a new one, oil analysis done, oil & filter changed. The damaged parts will be sent to Germany if BMW requests. ETA to complete this is 1 week, I'd guess 2 weeks more likely.

I'm at least the 4th person so far to experience this exact same failure. See above-ref'd thread for the others. I think in all cases there was no known preceding cause -- no crash, no mis-shift, no speed shifting, etc. Low mileage in each case (one had only about 2,000 mi.). Just normal operation, then one day the problem happens.
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