Originally Posted by JohnC
I'm guessing your friend is right, it's not the O2 sensor. Like he said, a bad O2 sensor usually yields bad mileage. But, hopefully your BMW mechanic is right, and it gets fixed. The first time!
I don't think your GT has the same issues as mine, but who knows? No idle issues on my bike, and throttle modulation below 3k RPMs is pretty smooth. All my throttle on/off issues are above 3,500 rpms. Mine feels like it has a bad spot in the TPS, but not really that either. Throttle roll-on is very smooth. But, there's a point when rolling-off that the throttle just shuts-down. If you hold the throttle right in that bad spot you get a nice bucking motion as the engine has a turn-on/turn-off sensation. If it was a bad TPS I would expect the problem to be more consistent. Some times it runs fine for hours, others not so much.
Try doing The Dragon when you can't reliably modulate your throttle. It took a lot of the fun out when we were there a couple weeks ago. Luckily I made one pass while it was working well. Fantastic roads
Thanks! I will print this out and bring to my dealer this weekend.
By the way... My bike does all kind of funny idling...
1) Stall > once in a while, it will stall when I down shift to come to a turn or stop. Bike is hard to start up without giving gas and hold on to the throttle to keep the engine going...
2) High Idling > Bike will start to idling around 1800-2000 rpm. This is very obvious when you are riding in the city and stop at the light. If you are in the twisty, this will make each turns very very dangerous...
3) RPM stay up and come down slowly > Idling seem fine but when you rpm you engine to any rpm, 2000, 3000, 4000, 5000 and so on... RPM will stay there for 1/2 to 1 second before coming down slower than normal... This might be what you experience... I have ride with my wife on the back and notice the bike rode very funny in twisty... later found out it was the rpm stay up there for a while before coming down... Make shifting worst than beginer!
I think we (06 k12gt and up) all the similiar kind of throttle problem... Hopefully, this is the fix for our problem... if not, BMW better come up solution quick... This is very dangerous!!!