99 R1100 RT - Surge is gone - Cheap Fix?!
Like so many of us my 1999 R1100 RT was a bucking, surging beast. I'd tried nearly everything to fix it. Plugs, fuel additives, octane boosters, "striction" valve adjusting, Booster Plug installation, cat plug juggling, etc. Nothing really helped me. I was flat sick of it to the point I stopped riding the bike and went back to my faithfully smooth 91 K100 (even as banged up as she is). On a warm winter day I washed the R1100 up with plans on trading it in or selling it outright. I wondered how I could honestly pawn this pig off on someone without revealing the annoying and common problem. I took her for a ride and stopped for fuel. I was so mad at the buck/surge I just dumped a very full tank of regular 87 octane in the tank! Put premium in such a pig, not anymore! Screw this junker was my prevailing thought.
That one defiant act was the best thing I've done so far to eliminate the surge issue! As I made my scoot home I immediately noticed the surge was lessening. At first I didn't believe it. Couldn't be, must just be a fluke. Turned out it wasn't! Now, nearly ten tanks of regular fuel later, I'm throughly convinced the composition of the fuel was a large contributing factor in my surging issue. Before this I'd tried multiple brands of premium fuel from different stations and the surge was always there. Since the switch to low octane I've done the same and the results are all the same. Smooth and surge free. The mileage hasn't changed and the plugs look great.
I have no idea whether this will help anyone else but wanted to share my "fix". It sure helped me. Since the fuel switch I've shelved my plans to replace the bike. It's running great and has allowed me to tear the bruised K100 apart for repair.
Additional requested information
You all have very interesting questions that I will try to adequately answer. Here is what I know:
[I]What coding plug is installed now?[/I] Stock Yellow
[I]Is your O2 sensor connected?[/I] Yes
[I]Do you have any add-on hardware still installed (e.g. BoosterPlug, Power Commander, or Techlusion)?[/I] BoosterPlug still installed
[I]Do you have a stock exhaust system?[/I] Stock w/ Cat
[I]Do you have the GS intake tubes installed?[/I] No - Stock
Admittedly it has not been hot here yet but the ambient air has been up to the 60's. So far I've had no hint of pinging. That certainly could change when it gets hot.
As for altitude changes, I've ridden the bike from 4500' to about 9800' in elevation without a noticeable difference in power, return of the surge or ping.
In truth I suspect if there was one real and permanent fix BMW (factory and aftermarket) engineers would have found it long. The myriad of changing variables makes it difficult to nail one down. For now I'm just pleased the fun of riding this bike is back. Come summer when the heads burn up from pre-ignition I'll be back crying in my beer about what I've done. I'm going to acquire a Swiss plug to prevent that catastrophe in warmer weather. Will it still be surge free or run right? Who know but it's worth a try. My odds of winning the PowerBall Lottery are probably a lot better.