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Thread: 99 R1100 RT - Surge is gone - Cheap Fix?!

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  1. #1
    '91 K100LT, '99 R1100RT theblueeagle's Avatar
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    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.
    Ride Safe - Be Safe

  2. #2
    Lucky motorradmike's Avatar
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    Interesting for sure.

    I can't help but wonder what is really going on.
    Good of you to post this, I think you've created a learning opportunity.

    Hopefully, 'Roger 04 RT' will notice and chime in, he's done a lot of work on the surging issue.


    So in short,
    Mike Marr
    1978 Yamaha XS750 (Needs rings), 1996 BMW R1100RS, 2004 Honda CRF230F

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    Registered User weeman's Avatar
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    I too have a surging r1100rsl beast but have been living with it since buying it last year. I will try your discovery as soon as the current fuel is used up. I never thought of using lesser octane instead of premium.
    If this works how nice it would be to not feel the surge!

    Steve

  4. #4
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by weeman View Post
    I too have a surging r1100rsl beast but have been living with it since buying it last year. I will try your discovery as soon as the current fuel is used up. I never thought of using lesser octane instead of premium.
    If this works how nice it would be to not feel the surge!

    Steve
    If you try it let us know but the air is thin and temperatures probably still cold in the land of theblueagle so pay attention to pinging if you do. Maybe start with a third tank of gas.

    At this point I think most surging is the result of leanness in certain open loop areas, made worse by air imbalances, and fuel injector imbalances. if, and it's a big if, more of the fuel can be burned inside the cylinder with regular that would, in effect, richen the mixture?a more perfect combustion. But I think we're a long way from concluding that.

    Keep in mind that there are plenty of lower octane, lower compression GSs that surge like mad.
    RB

  5. #5
    '91 K100LT, '99 R1100RT theblueeagle's Avatar
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    Additional requested information

    You all have very interesting questions that I will try to adequately answer. Here is what I know:

    What coding plug is installed now? Stock Yellow
    Is your O2 sensor connected? Yes
    Do you have any add-on hardware still installed (e.g. BoosterPlug, Power Commander, or Techlusion)? BoosterPlug still installed
    Do you have a stock exhaust system? Stock w/ Cat
    Do you have the GS intake tubes installed? 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.
    Ride Safe - Be Safe

  6. #6
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by theblueeagle View Post
    You all have very interesting questions that I will try to adequately answer. Here is what I know:

    What coding plug is installed now? Stock Yellow
    Is your O2 sensor connected? Yes
    Do you have any add-on hardware still installed (e.g. BoosterPlug, Power Commander, or Techlusion)? BoosterPlug still installed
    Do you have a stock exhaust system? Stock w/ Cat
    Do you have the GS intake tubes installed? 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.
    Thanks for all the additional information. Your fairly high altitude riding will make your motorcycle less sensitive to pre-ignition since it reduces the cylinder pressure, at least that's what I have read.

    Lesser surging on regular gasoline is something of a mystery to me and you have the option on your 1100 of the 30-86-87a coding plug which is for lower octane fuel.

    There is one real and permanent fix for surging. Mixture richening by lambda shifting at the O2 sensor does that job and Bosch & BMW are fully aware of it. I'm not sure why someone didn't get there before me but it works, is permanent and has good science behind it. The problem is that any modification of the fueling system (BoosterPlug, Powercommander, Techlusion, LC-1) is not legal except for off road riding.

    We can be sure that Bosch/BMW knew that richer mixtures were better because the European 1100s the shipped without catalytic converters ran mixtures about at the level that I'm running with the LC-1. The problem with the Euro config now, is that it is Open Loop and fuel with ethanol almost completely counteracts the Euro config fueling and you end up about 1% better off.

    Perhaps the biggest reason why others haven't proposed lambda shifting with the LC-1 before is a general lack of documentation on the Motronic's powerful adaptation value function. Powercommander introduced a PC III USB with Wideband sensor 7-8 years ago and when I asked them some questions, which they responded to in writing, it became clear to me that they only understand Open Loop fueling which is 99.9% of what they sell. They couldn't even describe the best way to set up the fueling table, pre tune on the Wideband product, nor do they advise an adaptation period before tuning the Open Loop parts of the table.

    So keep us posted on how this goes for you and enjoy the great, thin CO air.

    RB
    Last edited by Roger 04 RT; 04-23-2013 at 01:02 PM.

  7. #7
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by theblueeagle View Post
    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.
    This is an interesting report. I'm curious about the differences between premium and regular that might explain this but first I've got a couple questions:

    ?What coding plug is installed now?
    ?Is your O2 sensor connected?
    ?Do you have any add-on hardware still installed (e.g. BoosterPlug, Power Commander, or Techlusion)?
    ?Do you have a stock exhaust system?
    ?Do you have the GS intake tubes installed?

    You didn't mention pinging so I'm assuming that you haven't had that yet?hot, high pressure days at low altitudes could change that.

    The coding plug matrix says that there is a Swiss catalytic converter coding plug (lower octane I think) that grounds 86-87a-30. If you get pinging you might want to try that as I suspect it retards timing.

    RB

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