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RTP Running rough at idle.. what to look at first?


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Hi folks,


I just got my '04 R1150RTP with 100k miles (engine rebuilt at 60k).


It has a low idle at about 800 rpm, and even when I crack the throttle to get it up about 1100-1200 rpm, it is still running at bit rough -- missing ignitions, and sputtering a bit. It also struggles to get going from a cold start. When it is running under load out on the freeway, it feels fine.


Any suggestions on what I should look for first? Plugs? Coils? Valves? ... Sorry if this is a noob question, but I couldn't find it on searching.




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IT sounds like your idle air is set too low. Take a screwdriver to the BBS (Big Brass Screw) on each throttle body, and GENTLY measure how many turns it takes to tighten the screw gently into it's seat.( write this number down) You should get about one full turn to one and a half turns before it touches the bottom or the seat.


Next turn the BBS on each side to the left bringing them out exactly 1.5 turns, then start the bike and see how it runs.


Both sides should be close to the same setting.

Remember where they were set when you began.

There are a few other factors involved but to get the idle speed up to a tad over 1000rpm, the BBS's need to be out there a bit more than they probly are now. Get a Twin Max to syncronize the throttle cables so you get even flow on each TB as you ride for less vibration.


Read this link:



And download this pdf file and read it through. John Jen and Marc wrote the Oilhead Valve Adjust for Dummies (OVAD) book as well. All free, you are on your own kinda thing.



Good luck!

Sirby cool.gif

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Not knowing your mechanical skills, I would highly recommend a complete service to reach a base level. Once you have the valves properly adjusted and the TB's synched, the bike should run smoothly. If not, then it is time to look at air leaks from the stub pipes leading into the throttle bodies, especially if it was diffifcult to synch the TB's. Check the spark plugs for fouling and wear while you have them out.

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i have 1998 rt/p and was surprised by all the problems i found with the bike. it was a chips motor and was suposed to have been maintained by bmw of hollywood.shame on them.if you just got this bike with these many miles on it then be prepaired.I would start by checking compression,then throttlebody play at the butterfly shafts considering 100k miles.valve timing etc.etc .

start on one end and walk your way thru the bike.you will find all kinds of things.

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To answer your question, look at theses forums first. I once had faith in my BMW dealer to give me a correct, well tuned and balanced bike. $600 later it was left to me to have a go as my darling wife would not let me spend anymore at a dealer. (smart woman)


My suggestion, take the time to learn what has already been posted and more importantly have confidence in doing it. I made the homemade manometer, reset TPS, balanced and now have a bike that is a dream to ride. It may have taken 6 months for me to achive but it has paid off in the long run. Again, many thanks to the people who post. Especially Boffin and Twisty. thumbsup.gif

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