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.