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Running Rich


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My 97 R1100RT seems to be running rich some smoke on start up I checked the plugs and they are dry, black, and sooty. My question is how do you adjust the fuel air mixture on one of these bikes?

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Devo220, a little smoke on start up can be normal.. If you hadn’t ridden the bike a good distance at speed before removing the spark plugs they will be black & sooty..


A good indicator of your engine’s operational richness is what kind of fuel economy are you getting?


The fuel/air ratio on your 1100RT is basically computer controlled so unless someone has messed with the sensors,, or removed the CCP,, or disconnected the 02 sensor,, or added an aftermarket fuel controller there isn’t much you can do to change it..


I guess the fist thing you have to do is determine IF you really are running rich ..


What is you hi-way fuel mileage? What is you around town fuel mileage?


If you want to see if the spark plugs tell you anything install NEW plugs then run the bike about 20 miles at high speed--- then without idling the engine ,, shut the engine off,, coast to a stop,, allow engine to cool,, then remove the spark plugs & look at them..


Does your motorcycle have an aftermarket fuel controller on it like a Fuel Nanny or Techlusion? If so that could be set too rich..


LOTS of things can cause a rich running BMW 1100.. Could be an incorrectly set TPS,,, or a plugged or disconnected fuel return line,, or failed 02 sensor,, or faulty fuel injector,, or removed CCP,, or failed oil temperature sensor,, or failed fuel pressure regulator,, or severely plugged air filter,, or other???..


When do you think the running rich started? Have you used any fuel additives or fuel cleaners lately?


Sorry for the lack of any real help but the complex computer system on the 1100RT makes it difficult to just turn a screw & change the engine fueling..


If you can give us more history on your problem & when it started maybe we can guide you through other things to check..




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I have only had the bike for about 5 or 6 weeks, I bought it from a guy in Maryland. When I first got the bike it had a D&D aftermarket exhaust on it, and it wouldn't idle unles you kept the cold circuit open, He gave me the stock exhaust with the bike so I put that back on in hopes that that would help the idle problem, no luck. I made a manometer to check the carbs and when I went to set the big brass screws to 1 1/2 turns out as a starting point, I found they were closed all the way down. I opened them up and balanced the carbs now it runs good except iit seems to be running rich. Would he have had to change the chip when he put the exhaust on. and I didn't know? Could it still be there and where is it located so I can check.

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OK took the bike out and ran it pretty good for about an hour, doing 60 on the way back cut the power and coasted in. Let the bike cool and checked plugs, they were both a light shade of grey with no deposits. Still smoke on startup. The bike only has 7000 miles on it so it's still like new.

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It doesn't sound like the rings are broke in yet. Are you using conventional motor oil or synthetic? On both an older air head and K bike, I tried to go to synthetic too soon and both bikes smoked. Had to go back to conventional motor oil until both went over 20,000 miles.

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A 12 year old bike with only 7000 miles on it? There is the answer to your start-up smoke. In all probability the intake valve stem seals have dried out and are allowing a tiny bit of oil into the combustion chamber.


There is no real need to worry about this, unless the bike begins to consume a bunch of oil and you, or a careful observer riding behind you sees smoke under trailing throttle.


What that bike needs is a good thrashing. Now that you have it running pretty well, go find some hills and curves and spend a weekend running up and down them in second and third gear using all of the throttle along with all of the tachometer and a lot of coasting down under trailing throttle in the same gears. 4 or 500 miles of this will insure that your rings are seated and you can then use any oil you wish.


The last 3 bikes I have owned have gotten this treatment, oil changed to full synthetic at 600 miles and use no oil between changes. Waiting 20K miles to switch to synthetic, if you choose to use it, is just plain silly.


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I never thought of that but you are probably right. I will take it out this weekend and put it through it's paces change to full synth and not worry about it.

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Devo220, a little smoke on start up isn’t abnormal on a 2 cylinder BMW.. Smoke color will tell you a lot.. Unfortunately with a catalytic converter it is sometimes difficult to tell what you have as the cat. will try to burn it off..


Basically if you can tell smoke color on start up you might see:


Blue,, or bluish gray is usually engine oil..


Dark black is usually rich fuel..


Gray or white is usually moisture.. OR it could be a fuel additive like Sea Foam or Techron type additives..


If your smoke is jet black but otherwise it runs & idles OK with normal color spark plugs then maybe a dripping fuel injector during sitting parked..


If your smoke is bluish on start up then maybe parking the bike on the side stand is allowing some oil past the low side rings.. (try the center stand during parking as a test)..


You might also remove the vapor canister purge hose from either TBI lower nipple & see if that is fuel bound.. If so maybe a vapor can or control problem..





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