lumpy idle

[trouble]

I replaced my battery, fastening the pos terminal it grounded briefly
now the right cylinder is firing only when revved up,
I switched plug wires on coils but the right cyl. still has a cold pipe.
any help much appreciated

[carl1957]

Check to see if the throttle cable is seated, not hung on the edge of the throttle body. Always when disconnecting the battery, after re-connecting before starting the motor, turn the key on. Then twist the throttle three times to full, the turn off the key. This re-calibrates something or other… I'm not one of the techs here.

[trouble]

thanks, that sounds like the routine when I locked my keys in the 740i with no battery

[CycleRob]

trouble, What happened to you is quite common after the fuel tank is removed and replaced. The right side throttle cable is so short, there is no free curvature slack in its length. Any sort of tug on the visible part of that cable pulls the TB end cable ferrule out of the adjuster socket. Because the TPS on the left TB determines the fuel mixture for both cylinders, it only provides the idle mixture to both cylinders -while- the right TB, with its throttle cable now accidentally dislodged from its proper position, feeds a massive amount of plain air. The bike runs on only the left cylinder unless you whack on a LOT of throttle, then the right cylinder runs but not correctly. The left exhaust pipe and the CatBox will glow reddish while the right exhaust pipe is cool.
Turn off the key and reinstall the right side throttle cable:


After that you should reset the TPS and all other EFI component values to their first run status. These harvested pics show you how:
1-- Remove fuse #5 for 10 seconds then replace it, to fully reset the Motronic computer.

2--Turn Key and kill switch ON, tranny in Neutral.
3--Twist the throttle at normal speed from the idle stop to the full throttle stop and do it twice, to send the correct throttle span position data to the Motronic ECU.
4--Turn the key off. You're done and ready to go!

Since the fuse was removed (or when the battery is disconnected) the Motronic memory gets reset to 'first run' status. That means the fuel mapping data that was trimmed (optimized) by riding the bike gets lost and it will be recreated during normal riding. You may notice lessened engine braking force on your first downshifts - - - that is normal and it will return soon. Resetting the Motronic is a good and easy first step to possibly cure an erratic engine idle or running condition if the Motronic's fuel map gets corrupted by any number of things classified as an "electro-magnetic disturbance". Rapid starter button presses or loose/fuzzy battery terminal(s) top that list.

[Hoof]

Thank you for your fine article - the description of poor running after tank removal exactly matched my problem but 'interestingly' the cable was correctly set at the TB ..... eventually (many many hours) I found the cable at the bowden box end had pulled out about 5mm and stuck there by friction on the dry grommet which is tucked out of the way and not obvious.
Pressing it back in immediately solved the running problem. As this seems unusual I thought I'd mention it on the forum as a worthwhile check as even the smallest mm displacement here is worth checking before tuning.
Others thanked elsewhere with recent posts (if they don't disappear) but your detailed article of symptoms led to my solving the problem. It had to be the cable but from all the descriptions and pictures it was properly seated.... but not at the other end! Many thanks again.