super fast idle

[bigm]

r1150r with 2700 miles has been sitting in my barn with a dead battery for 8 months. i noticed the electric plug to the left injector was disconnected. after reconnecting, i jumped it by removing the starter cover, and jumping from the starter. it started up but ran at almost at 5k rpm. shut it down asap. i fiddled with the injector and noticed fuel leaking. i thought maybe air was getting in and causing some crazy sensor issue, so i removed the injector, and lubed up o rings. it stopped leaks. i started it again. same issue. throttle cables seem to be working properly. any suggestions? thanks. .

[NoRRmad]

Try resetting the Motronic computer. First, make sure the battery's fully charged. Switch on, but do not start. Turn the throttles all the way up, twice. Switch off.

Then try starting normally. After it starts, make sure the "fast idle" lever is down.

(This may not help, but it's quick, easy and cheap -- a good first step in the troubleshooting process.)

[michelsmith]

I remember having something similar on my '01 SC2. It would sometimes have a low idle, and it would also randomly idle high. It was the throttle position sensor. I figured it out by catching it during one of its bouts of high idle. I opened the hood and jiggled the TPS and the idle went to normal. The part was fairly cheap and easy to replace.

[bigm]

new bmw battery. now will not start. seems like no fire. i will check for spark, then address injectors. back in the day it was either carb or spark. now things are much more complicated. one day i will ride again, even if i have to trade for a classic.

[CycleRob]

bigm,

Revving over 5,000 RPM is only possible if the throttle butterflies are opened. If it was a vacuum leak, there would not be enough fuel injected at closed throttle for the engine to run.

Work the throttle from idle to full and listen for the "tap" sound when you return it to idle. If you do not hear that tap sound on BOTH TB's, then:

1-- The throttle cable may have been pulled out of the throttle assembly just downstream of the twistgrip housing.
2-- The throttle shaft and/or throttle butterfly are gummed up and sticking partially open. You may have to pull back the black plastic intake tubes so you can shoot quick short shots of carb clean at the butterflys and all 4 shaft bearings. Use a paper towel to quickly soak up the excess -or- better yet, remove both TB assemblies so the carb clean and gritty gunk it removes does not go into the combustion chamber.

When it's all cleaned or the throttle cable has been reseated, the closing throttle "tap" will easily be heard, on both sides. You'll also need to reset the Motronic memory any time the battery is disconnected or dies. Here's my old copy-n-paste of that procedure:


Anytime the battery is disconnected, you need to reset the bike's Motronic computer memory. It stores the closed/open voltages of the left throttle body's TPS unit spanning the throttle's operating range that controls the fuel injection and ignition timing.
1--Remove the 5th fuse from the left (gearshift side) in the fusebox under the seat.
2--Wait 10 seconds for the previously stored memory readings to die.
3--Replace the fuse.
4--Turn on ignition key and kill switch, trans in neutral. No starter!
5--Turn the throttle from idle stops to the full throttle stops twice.
6--Start engine to ride bike -or- turn key off and walk away.
My experience: With the CatCodePlug in place, engine deceleration braking will be weak at first until part throttle 6th gear cruise/running optimizes the fuel map as your bike is ridden (completed in less than a half hour). This Motronic reset is a good idea if your bike's idle becomes temperamental and it's mandatory anytime the battery power to the Motronic is interrupted.