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

  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

  3. #3
    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 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

  5. #5
    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

  6. #6
    '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

  7. #7
    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.

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    I know, most people here don't like to hear this, especially the "proficient shade tree mechanics" but surging, in almost all cases, is the result of too much self-maintenance lacking proper equipment and poor throttle body synchronisation.
    I have a 1999 R1100RT for almost 12 years now and it NEVER had any surging problems. It did go to regular maintenance at a good service dealer, however.

  9. #9
    Registered User roger 04 rt's Avatar
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    While it is possible to misadjust the valves and throttle body balance, and exacerbate the problems of rough running at small throttle angles, it is easy to do right. Moreover, many dealer maintained bikes have the symptoms and many of those riders come to forums like this one looking for answers their dealers haven't provided in the 20 years that Oilheads have been in production.

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    Quote Originally Posted by Roger 04 RT View Post
    . Moreover, many dealer maintained bikes have the symptoms .
    Probably because these dealers do not have the qualified service personnel that they should have. I have experience with and knowledge about 4 BMW dealerships in my area and the quality of service work varies greatly because of the qualification of the people performing it.

  11. #11
    24991 Pauls1150's Avatar
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    Dealers are "supposed" to have mechanics who are trained by the BMW school...
    But being Authorized Dealers and Certified Mechanics (of various levels and specializations), they ARE NOT ALLOWED to deviate from the Holy Factory methods and specifications. Remember the painted screws on the throttle bodies and TPS's - If you find an 1100 or 1150 today whose paint is still intact, it probably isn't running as well as it could. I agree whole-heartedly that "who" does the work makes a huge difference.

    Interesting thought about the lower-octane fuel, though. I recall reading somewhere a while back that arsonists prefer to use lower-octane fuel; I think this was because it actually burns slower than than premium. Since it is somewhat cheaper than the high-test stuff, and considering that the cheapest item on our bikes is the nut that holds the handlebars, this becomes more significant.

  12. #12
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by EMSimon View Post
    Probably because these dealers do not have the qualified service personnel that they should have. I have experience with and knowledge about 4 BMW dealerships in my area and the quality of service work varies greatly because of the qualification of the people performing it.
    I hear you, but it is just not that hard to adjust TB balance and valves.

    The toughest thing for everyone, and it's the subject of this post (http://www.bmwmoa.org/forum/showthre...rging-buckling) running alongside this one, is fuel balance. It's impossible to measure or adjust and is likely the root of many performance problems. Many angst over getting the TB Balance and Valves adjusted to the nth degree but run with injectors that are mismatched by several percent. Even the best dealerships lack the equipment to measure the fueling effect.

    It isn't just the Air Balance that effects running quality, it's AFR and that weights air balance and fuel balance equally. Most likely, you're one of the lucky ones who have very closely balanced injectors--statistically it has to happen. Just as likely though are injectors, from the factory, imbalanced by several percent. Without replacement or mixture-richening, those bikes can't be air-tweaked to run well. So those with naturally well-balanced fuel injectors, who do a good job with air balance, become sure that air balancing is the answer--but of course, it's only half the equation.

  13. #13
    Jammess jammess's Avatar
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    You know I kind of agree that better running results from use of lower octane fuel (regular) in some cases. When I could get non-ethanol regular my 04RT seemed to run somewhat smoother and did get slightly better fuel economy. Now, however, the only non-ethanol I can get is 91 octane premium which I use almost exclusively.

    I have installed an LC-1 and just had my injectors cleaned and flow tested at RC Fuel Injection and all I can say is: WOW!! Plan on injector cleaning at least every 3 years from now on. Also, pay attention to Roger when he talks about the benefits to installing a wideband O2 sensor system because it literally transforms the oilhead motor. Before I never used 6th gear but now top gear is completely usable thanks to the increase in lower RPM torque.
    Jammess

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    Registered User boxwrench's Avatar
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    SRY but I hafta ask. Is surging when you let of the throttle a little and rpm drops like a rock and the tries to nose dive and the when you do speed up a little ( slow traffic and stop' n' go the opposite happens.

    If so MY 2000Rt does that and can't seem to get rid of it even w/ a stealer tune up.
    2000 R1100RT opal blue "Millenium Falcon"
    2006 Suzuki C50 Boulevard blue/silver w/ DJ drive mod.
    "Gator"

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    surge

    For those of you who have not experienced it, I define surging as a momentary miss right above idle. Basically the mixture goes rich when you roll the throttle on and the ignition system can't quite ignite it. There's a moment of hesitation and then it recovers with what feels like a surge of power. Annoying at best. Much of what I have to say is "ditto" - on a big twin it is necessary for the throttle bodies to be synchronized, from idle to all the way open. You will find on the internet procedures for doing that, and you will also find procedures for re-zeroing the throttle position sensor. I cannot recommend touching the TPS unless you have reason to believe it is worn out. You will notice a dot of paint on the setscrew. That's a clue.
    I had surging and other misbehavior - most annoying was refusal to idle at stoplights. When I tried 93 octane gas it would almost not even start.
    It wants 90 octane and I have found that you are better off with 89 than with 91. That said, I do get pings and rattles even with 89 octane.
    Ok, so, I replaced the plug wires, and I went to a 4-electrode Bosch spark plug. I took off the throttle bodies and cleaned the varnish out of them. I found that the bodies were out of synch only at idle, so I adjusted the idle stop screws.
    New air filter. I had a hall effect sensor failure and when I replaced those I took care to go with the factory setting, nothing fancy.
    Basically the Motronic on the 1100 doesn't provide quite enough energy to the coil, and also does not adjust ignition timing to deal with various gas octanes or pinging conditions. Also the O2 sensor is the on/off variety so at idle the ECU is dithering between too lean and too rich all the time.
    So there are a number of things you can do to improve it but it will come back as your plugs, plug wires, throttle cables, etc. wear and the air filter gets dirty. I'll dig up the spark plug code and get back.

    oh, forgot to mention - the lower octane rating means that the fuel has a "lower heat content" - it vaporizes more easily and ignites at a lower pressure/temperature than a fuel with higher octane. The lower octane fuel actually delivers more energy, which I find counter-intuitive. A higher octane means the fuel needs more pressure (higher compression) or more heat (hotter spark) to ignite, and once ignited will burn in a relatively slow spherical "flame front" that expands from the spark plug out to the edges of the combustion chamber. Ping and preignition are other names for detonation. Detonation occurs when the air/fuel mixture burns spontaneously all at once; essentially an explosion. There are several possible causes but in a stock engine it is normally low octane fuel.
    Last edited by scott.lambert; 04-28-2013 at 01:41 AM.

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