Good Day Fellow R1100S Owners!
Some time ago, (a long time ago) I posted my bikes poor above idle running issues (stumbling / Partial cutting out) I called it. I read in another BMW forum that one owner suggested trying pulling the lower plug off while the bike is running to test the Stick Coils on each cylinder.
Recently I have begun to re-diagnose this running problem. I haven't been able to give the bike the full attention it deserves till now. It has 42000 miles in it and I am suspicious of the stick coils acting up and misfiring at about 1200-1300 rpm just as I want to get on the throttle to drive away from a stop. Once underway at road speeds (any speed) it runs just fine. This rough (partial stalling) issue comes back again at what I call parking lot speed.
Today I started the bike and after a short warm up with the bike on the lower of the two fast idle notches I pulled the lower plug wire off the right cylinder and the bike sounded terrible and seemed to be running on one cylinder. When I reconnected the lower plug wire with the bike struggling to remain running a load bang was heard from the exhaust pipes. I assumed this was unburned fuel mixture when the right cylinder reignited the fuel air mixture.
The left cylinder behaved similarly when the lower plug wire was pulled away, but not to the extreme of the right cylinder. It too caused very poor idling on the high idle setting.
So it looks like my stick coils are toast. Just to add I have balanced both throttle bodies using the Twin Max device and have adjusted the idle mixture screws much earlier in the history of this bike and I am sure there are no issues with the throttles.
I also much earlier is the bikes' history replaced the stock Fuel Injectors with the rebalanced (improved) fuel injectors from Germany. I still have the stock ones and was surprised that the stock ones have the same four nozzle pattern as the socalled improved ones from Germany. Perhaps they are also to blame for the running issues with this bike?
Any suggestion here are well appreciated.
Thank You Guys,
Hans...
