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I'm posting this here, as this part of the forum is where I figure I should do so. Also, there is no introduction section for the forum that I could see.


Anyway, my name is Sean. I'm a 23 year Air Force Veteran, retired now for some six years. I worked Mobile Heavy Equipment for about 14 years of my active duty career, and am doing so again as a DOD Civilian.


The machine in question here is a 2001 R1150GS. It is not mine, but I currently have possession of it. I'm not here to give effusive praise of it, rather to figure out what ails it.


The question I have is related to running/idling issues. Keep in mind, I have over 20 years professional experience with engines and other mobile equipment systems.


When I took possession of the GS it ran fine. I was growing somewhat fond of the quirky way it did things (as compared to my Ducati and Aprilia) until the day it tried to kill me.


After replacing all the brake lines due to sudden brake failure in traffic, out of the blue it started running quite rough. It would no longer idle without throttle...like it was running on a single cylinder.


Sensing that it simply needed to be run, I took it to the gas station, topped off the tank, and poured 1/4 bottle of fuel system cleaner in. Ran it about 100 miles this weekend and it was actually running nice and clean on the highway.


At least, on my way home, after about 80 miles of riding. Prior to that, it had a stumble on constant throttle regardless of RPM.

If I were rolling along at a constant speed, it was like repeatedly getting a dead cylinder. Rolling along it's fine, and boom......boom....then fine again for 3 or 4 seconds. This cycle would repeat regardless of gear or rpm.


Didn't matter if it was above 4K or below. I ran it in 5th for a time, rolling on the throttle at 4K up to 5K and backing off. Pulled fine. Obviously, both cylinders firing like they should.


Then, once I neared home, I slowed to normal city speeds and the misfire/stumble returned. Really bad off the bottom, until I'd get to about 2500 rpm, then it would pull cleanly when I released the clutch lever. It would idle, but again, like it was running on one cylinder.


Throttle roll on prior to clutch engagement was a crap shoot. One launch would be fine, the next border line stall, before seemingly both cylinders would kick in, then not, then kick in again. Made for some hairy launches off traffic signals in traffic.


I pulled the plugs to see how they looked, and they were completely fine. Cleaner than probably 90% of the plugs I've ever pulled. The left plug was a bit too clean and there were some white looking marks on the electrode. Looked like it had been running really lean.


I checked to see there was a vacuum leak and all the hoses are fine. I'm down to either injector o-rings or a shorting/open wiring to the left injector. My question is, is there something I'm missing here? Like maybe something common that has been dealt with over and over that a BMW newb like me would not know about?


I've researched ad-nauseam over various BMW forums and videos and can only come to the conclusions I've listed. Thanks if you can help.........sean



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Hello Sean,

There are some very knowledgeable people here so hopefully someone will pop in and know exactly what to tell you. Based on your description I question either a coil or plug wire, possibly a plug. I've seen coils do this at lower RPM hot or cold.


Thanks for your service and good luck



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After replacing all the brake lines due to sudden brake failure in traffic, out of the blue it started running quite rough. It would no longer idle without throttle...like it was running on a single cylinder.




Given that the problem started after some work on the motorcycle the place that I would start is to make darn sure that the R/H throttle cable is firmly & fully seated in it's adjustment furrel & not sitting on the top rim of the adjuster furrel at the R/H throttle body.

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Thanks for the replies. It is definitely fuel related rather than spark related. The lean running indication from the left cylinder is why I think that.


I'll take a look at the right side throttle cable ferrule. I don't know how or why that would or could have changed from the original condition as I didn't touch it or anything associated with it really.


When I replaced the brake lines (with Spiegler kit) I lifted the tank, I did not remove it. I propped it up with a length of 2X4 at the battery. I bled the ABS but at no time did I tug or pull on any wires.


I did cut over a dozen zip ties but all of them were associated with the wheel sensors (or the lights on the fork tubes) and were zip tied to the brake line. I don't recall ever touching a throttle cable or cable housing...thanks again...sean

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I concur with checking both throttle cable seats at the throttle bodies. I've had that same experience several times. They have a lot of stretch to them and seem to get tugged away very easily.


I thought the 1150s got better HES wiring - but maybe not. His experience sounds a lot like mine (99 1100), which I've put down to HES wiring.

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Thanks Jim,

I checked today after work, and found the right side throttle cable housing was pulled up, out of the barrel adjuster. The cable housing ferrule was resting cockeyed on the edge of the opening.


Seems the fuel hoses run from the tank right next to the throttle cable. Lifting the tank pulled the hoses up, and consequently the cable housing up along with them.


Took a finger and slight push to re-seat the housing and a further push to move the fuel lines slightly inboard of the cable housing. Fired up and idled like normal.


So, huge thanks to you for that tip. The GS will be going back to the owner in a day or two. Many thanks once again.........sean

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I resolved the issue per my previous post.


I am just across town from you, on the other end of Fairfield.


The GS, is going back to its owner this week. He and I work together and it was on loan to me as he hasn't been able to ride. As my "contract" with him was to ride it, and I've spent more time working on it than riding it, it was decided that I should return the GS by my CFO. My chief family officer.


She was tired of hearing me cursing about how little riding I was getting versus the amount of work I was doing. When she brought up that my Ducati was less work, it was time to cut my losses and return the GS. I'm all for "paying" for my riding time with some maintenance work, but hell....I've spent more time working on the GS than riding it AND my 996 combined.


Hopefully, I won't be here to ask how to fix what breaks next....that will mean I never got the GS back to its owner......sean

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Happy to help. Glad you got it sorted. Every oilhead owner has done that at one time or another. That's how we all know.

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Delivered the GS to the owners storage today. After the ride in to work went completely smooth, I was beginning to have second thoughts about returning it. However, as agreed, I rode it over to his storage after work.


I talked with him about this the last few days and he's decided to sell it now. I was "riding" it for him because with 3 kids he has no time to ride it. Needless to say, it has been an experience. While I don't care to repeat the near death experience, this forum was a life saver.


While I didn't join until near the end of my time with the GS, I did cruise through looking for answers for the issues I encountered. I was able to find all the answers here...even when I had to join to ask a question I couldn't find a definitive answer to.


Also, while I no longer have a BMW, I'll check back in here from time to time. Ya'all have been great......sean

Edited by Justdontcare
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