Help, throttle control issue on my GS?

[mkletecka]

The problem I’m having with my new 2009 R12GS (about 3K miles on the clock) is an engine on/off effect when quickly rolling off the throttle, which is very annoying and experienced when the throttle is feathered between its opened, closed position and if I let the throttle go to its closed position, it gives the impression/feel that the motor has died, then at that immediate point when opening the throttle it abruptly comes to life again (please note, there is no surging problem).

This on/off sensitive throttle causes strong drive line lash/upsets the bike in the handling department and requires an immense amount of concentration/hands of a surgeon to keep this from happening. Anyway, I understand that twins have heavy engine braking (this is my fourth BMW twin) but this GS/throttle control issue is ridiculous. I have complained to my dealer, but they say the bike checks out ok. Anyway, is there anyone out there that has experienced this problem and more importantly has a cure for it? Any help will be greatly appreciated !!!!!!!!!!!!!

Kind Regards:
Mike K.
Dana Point, CA

[signit98]

Oddly enough, the characteristics sound similar to what Jeff Williams is experiencing with his HP2...

Everything else is "normal"? I'd point my finger to a faulty TPS... maybe an intermittent problem!? Unfortunately, with today's overload of electronics, the problem can be manifold but with the symptoms you are describing... that's as close as I would guess.

The trouble with today's mechanics is that they are not willing (or just don't have the time) to go the extra mile anymore... everything is computer diagnostics and if the computer says the bike is ok, it must be, right?

Every tech hates intermittent stuff and most run away from it... find someone who has a passion for finding and fixing things... though under warranty, it might pay off to get an independant look at it.

[Peter Parts]

Idle too low?

Sometimes shops like to set idle fashionably low and/or to meet an unreasonably optimistic low spec. But then it can be too low for practical riding. Esp. for a twin with a vestigial flywheel.

Don't touch the butterfly idle stop screws. That's a factory calibration. Use the air by-pass. Not especially risky to crank 'em up (that is, out) a quarter turn, if you can return them accurately to their initial setting. Ever wonder why adding air makes the bike idle faster? On an EFI bike, ought to make the A/F leaner, eh?

Might relate to Jeff's off-idle power issues too.

Sure nice to attach dual vacuum gauges for diagnostic purposes.

[SergioK]

Wow, that sounds like BMW's new 'fuel saving' feature on some of their euro cars, maybe it has the new "Efficient Dynamics" technology package.

Which dealer did yout take it to? I assume that when they say it checks out OK that the GT1 reports no error codes?

[mkletecka]

Thanks Signet 98 & Peter Parts

Thanks for answering my question!!!!!!. Prior to asking this I was getting nowhere, in fact some said to just ride around it (BTW, I did not have this problem with my old 12S). Anyway, with your information I can now go back to the dealership, or worse case go to an independent repair shop and get this issue resolved, or greatly reduced.

THANKS AGAIN!

Mike K.
Dana Point, CA.

[RBMann]

I don't know if they are the same but on the R1100S, it cuts off the fuel to the injectors when you close the throttle. The moment you open the throttle there a little burp as it get fuel again and starts running. Most noticeable at lower RPMs. There is also a lower RPM limit where the fuel comes back on even with the throttle closed. This allows fuel for idling.

On the S if you close the throttle at say 3000 RPM in fourth gear then let it coast down, it will burp and start running again around 1500 RPM.

Good luck,

[Peter Parts]

Originally Posted by RBMann

I don't know if they are the same but on the R1100S, it cuts off the fuel to the injectors when you close the throttle. The moment you open the throttle there a little burp as it get fuel again and starts running. Most noticeable at lower RPMs. There is also a lower RPM limit where the fuel comes back on even with the throttle closed. This allows fuel for idling.

On the S if you close the throttle at say 3000 RPM in fourth gear then let it coast down, it will burp and start running again around 1500 RPM.

Good luck,

Yes, that's the essential software pop-back switch that some people think isn't there. But it shouldn't be causing any burping.

The R1100S gets blamed for a lot of pop-back on deceleration when it is the rider's fault for not closing the throttle fully in order to activate the software switch and in a split-second after then settling on the appropriate throttle setting. That settling is greatly aided by having a throttle counter-force spring, of course.

I wish somebody could explain the parameters of this switch to us - I'm foggy on the details. Oh boy... I see a reply coming now.... long on jokes about "foggy" but real short on substantive stuff.

[boxercup]

Greetings Mike,

Nice Bike! - Good Luck with it! How are you?

_______________________

Is your bike stock or performance modified?

If so please describe.

I can help!

[mkletecka]

Robert:

As always, great speaking with you. In closing, thanks for going over my problem with me in detail. I'll keep in touch with you to see how you are coming along with the fix. (......wonder whats in store for us if "Euro 4" comes out? ha ha)

Kind Regards:
Mike K.
Dana Point, CA.