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Can you diagnose this problem?


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I'm having an issue on my work bike, a 2008 R1200RT-P. I wonder if the experts here can suggest what they think this issue is.


My first symptoms were that if you pulled in the clutch as braking to a stop, the RPMs would not drop to idle, the engine would just die. That same day it would occasionally idle very rough. I ended up reaching in and wiggling the wires leading to the ignition coils. After restarting the motor it ran great for a couple weeks.


When the same symptoms came back, the bike went to our BMW trained city mechanic. He replaced the ignition switch and found that each throttle body had cracks in a plastic part, so they each were replaced.


The bike ran smoother & had a bit more power when I got it back. It idles great & has not died since. The symptoms have changed now. When rolling off the throttle to slow (clutch still engaged) it decelerates normally until about 3k RPM, then the RPMs don't want to drop anymore... which almost feels as if the bike is accelerating, since I'm expecting RPMs to continue to drop off.


Today I was playing with it and realized I cannot make the engine hold a steady RPM anywhere between idle and 3k RPM (I did this while stopped with the engine running). If the engine is idling and I twist the throttle only slightly, the RPMs jump to about 3k. If RPMs are 3k or higher and I slowly roll off the throttle, they decrease as expected until 3k, and then drop right to idle. If you try to hold RPMs at 2k it is completely impossible. It will only idle or jump right to 3k RPM.


I'm dropping it off for repairs again tomorrow. I'm hoping you can give me a suggestion on what it might be, so I can pass that along to our mechanic.



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Morning Scott


Some possibilities on this one but more info on when the problem started & how it progressed could sure help us pin it down closer.


Such as-- any work or service done to bike before issue appeared?


EXACTLY what plastic parts were replaced for last problem?


I guess lacking more info the place I would start looking is for

vacuum leaks between TB's & cyl head,


TPS tracking issues or TPS wasn't reset after battery disconnect service,


BROKEN THROTTLE CABLE adjusters right where cables enter TB's (need to look closely for this),


R/H throttle cable not routed correctly over air intake snorkel,


Fuel pressure issues due to FCP not correctly controlling fuel pump,


Stepper motors not properly following throttle position changes,


Stored fault codes in fueling computer,






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The entire throttle bodies (both side) were replaced with new OEM parts, not just a piece on the throttle body.


No previous issues with this bike, and no recent service/repairs done before symptoms arose.


I'll have to wait another week before it gets looked at, mechanic has some other work in front of my bike. Thanks for the tips. I'll let you know how it pans out.

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The pulleys on my RT broke last January. I recall others saying it didn't happen. I guess it does. Actually, a member of the Forum did an eBay search for throttle bodies and half of them had cracked pulleys...I replaced mine with used units from a low mileage total. I got the distribution box and fuel injection setup with the throttle bodies for $265. New throttle bodies were 1100+ plus labor and that doesn't include the TPS, steppers and fuel injectors. Whoever did the work needs to look it over again. It could be that they transferred the old parts and something is not right with them or the throttle cabling is munged up. No matter what, the tech needs to recheck his or her work.

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The issue was one of the throttle bodies. The tech was already suspicious of it... Said something wasn't right from the factory & he had attempted to fix it. Replaced with a new one, runs like a champ again.

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You don't have to replace the whole TB.

Just the throttle shafts with new Bing cable pulleys attached. They are still metal/plastic stupidity but that's all available.

Usually it's the RT-P's that really go thru these. Thought to be the many heat cycles making the plastic brittle.

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You don't have to replace the whole TB.

Just the throttle shafts with new Bing cable pulleys attached. They are still metal/plastic stupidity but that's all available.

Usually it's the RT-P's that really go thru these. Thought to be the many heat cycles making the plastic brittle.


So BMW would know about it you'd think. I put in a NHTSA complaint on it and I wasn't the only one.

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Oh, they know alright.

Depending on the age of the bike, the helpfulness of the service manager, BMW has warranteed the parts or half the parts out of warranty.


The shop I work for developed the tooling to make it possible to replace just the shafts and the end plates using Bing parts.


The end plates really can't be removed from the old shafts without damaging or destroying them so the easy answer is to join the new from Bing plates and shafts and replace as an assembly.

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For me, they wanted me to submit a receipt of the repair at a dealer and then they would consider it. That's a $1400 bet I wouldn't take, so I found a set with all the throttle linkages and fuel injection for $265 from a low mileage salvage. If they covered it, I would have had it done, but like everything else with BMWs, Eilenberger's Axiom applies. From a post of Don's on this forum, I think, to do with the fuel pump flange issue. It applied to a lot of stuff.



"I'm betting BMW's solution will be some sort of clamp on ring, with a special tool to install it (probably an Oetker type design) allowing the dealer 30 minutes labor time to do the job (regardless of bike model..)


And I'm sure based on BMW's usual reactions to these sort of things:


1. What problem?

2. Oh, that problem. First we've heard of it.

3. You caused it

4. Your environment caused it (fuel properties usually)

5. We have no problem


Is at step #4 now... so I'm certain they've never heard of the problem in Europe.. (said with tongue firmly in cheek..) It's caused by bad US karma."

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Every manufacturer does the same thing.

HD with the fuel pump issues on the big twins, etc.



Edited by Tri750
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  • 2 years later...

This happened to me a couple weeks ago to my '09 RT-P. I was resetting the trip odometer at a gas station so fortunately I wasn't moving.


Twist the grip and crunch. Both pulleys gave way. Naturally the dealer never heard of this happening before. Complaint in to NHTSA.


Bing lists the pulleys on their website for $19.95 but its not clear how one replaces them.

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Dennis Andress
The entire throttle bodies (both side) were replaced with new OEM parts, not just a piece on the throttle body.


An old friend wrenches for the Arizona Hwy Patrol. He sent me pictures a month or so ago of two throttle bodies with the plastic pieces the throttle cables attach to completely sheared off. At $1000 a piece for throttle bodies they retired the bike.

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I've not had a need to learn how they are replaced, but there is a technical assistance phone number at the link. Call and ask about the procedure before ordering? I doubt they would sell the individual pulleys if they could not be replaced.


Wrong. Bing sells the pulleys alone, the throttle shafts alone, the circlips on the ends alone, but has no tool or data on how to stick them all together to replace them.

Charlie at Bing is a good guy, he emailed Bing Germany asking about pre-assembled throttle shafts with new pulleys, nope. Asked about how customers are to join the bits together. No solution. They sell the parts.


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I've not seen these but I see they are attached using pins AFTER you drill three holes in the end of the shaft.

I don't know if my Harbor Freight drill press would be precision enough to drill 3 tiny holes in the end of a tiny shaft with any success.

The shafts are pretty hard.

The price is pretty dear as well. I know more than anyone they have to recoup their cost of having these made, but normally you do that with good marketing and lots of sales, not trying to recoup on the first 10 sets you had made.

I would like to see the instructions .

Maybe I'll ask to see them.

Thanks for the info.

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  • 2 weeks later...
a you tube visit






Bing $40/pair

Beemer-Bits $450/pair



New addition to winter project list: Reinforce throttle pulleys with aluminum plate and JB Weld

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