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Discussion Starter #1
Hi all,

Im relatively new to my 99 k12lt, but i had a chance to take it on a long ride before this problem and can tell there is a problem. So, on with the story.

I rode to work just fine no prob at all. let the bike sit on a sidestand all day 8hrs leaning it slightly downhill (the pistons facing downhill) Ive done this before and no prob but i thought it was worth note. when i started it up i got the usual smoke no big deal. but i also noticed it had a bit of trouble getting the bike to start from a stop. I thought it was because it was started cold and i was still sort of new to it. so i went home and continued to take it on a 100 mile trip to a friends house. again i noticed it would not start from a stop well I also noticed that while on the freeway at 80mph or so in 5th gear i was having a hard time accelerating. Im not talking about anything crazy i just couldnt get it to go faster than 80mph without downshifting. this is not normal as my last long trip i could easily do this. also i noticed i was getting around 30mpg as checked when i did the math on the mileage vs. what gas i bought. that isnt right from the posts ive read or from my other long trip experience where i got 42 mpg going from 80 to 90 mph most of the way. last of all i noticed there is a bit of a loudness that wasnt there before in the engine area and a specific lugging sound at 3400 to 3800 rpm in all gears while in that range. my first thought was fouled spark plugs I havent tried the tps reset yet but i think i may be dealing with something more than that (and i havent disconnected my battery in a long while) Oh and no unusual lights on in the dash area (do these even have an SES light?)

In summary
poor mpg
poor acceleration
noise 3400 to 3800 rpm
no warning lights

whats wrong braintrust? thanks for any advice you have or tips on figuring this one out.
 

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Discussion Starter #2
Ive thought of that as well but dont want to call it that just yet. seems too easy of a culprit. Ive always used either seafoam or chevron techron. the seafoam though according to GM can eat away the turn plate coating in (their) gas tanks. does BMW use some sort of tank coating? I havent looked but isnt the tank on the bmw plastic? which means i could use seafoam. again not ready to blame fuel just yet especially because ive run most of 2 tanks as a result of the poor fuel economy.
 

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If your mileage is in the low 30's I would suspect the O2 sensor. Mine went out and I dropped from 42 down to 26.

dan
 

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Discussion Starter #4
did you also have acceleration issues? It would make sense. Is there any way for me to check without something to interface with the computer (say like unplugging it?) does it run at a default when its unplugged or just not at all?
 

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Carsucharda said:
did you also have acceleration issues? It would make sense. Is there any way for me to check without something to interface with the computer (say like unplugging it?) does it run at a default when its unplugged or just not at all?
I don't recall acceleration issues. Had a strong smell of unburned gas when sitting still.
 

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Discussion Starter #6
so yours failed on the rich side. im guessing if mine failed it failed lean. mine does not smell of unburned gas at all nor do i get any black smoke on accel
 

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my guess is you have got bad fuel and the filter is clogged, could explain low mpg the o2 sensor is a maybe wouldnt hurt to check it. I wouldnt worry about fuel cleaners until after you drain the tank and renew the filter then you can confirm the disconnects are in good order as well as the lines on the filter. (fuel smell) run the fuel cleaner in the new gas to assist the injectors
 

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Carsucharda said:
Hi all,

again i noticed it would not start from a stop well I also noticed that while on the freeway at 80mph or so in 5th gear i was having a hard time accelerating. Im not talking about anything crazy i just couldnt get it to go faster than 80mph without downshifting.
I think this is an accelleration issue
 

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If your 99 still has the stock rubber brake lines, it's time to change them to steel lines before one of the stock lines springs a leak.

If I was going to remove the tank and change the fuel filter I would also change the air filter.

Take pixs of the bolt arrangement for the rear of the gas tank; first time I did mine, I got the sequence of parts incorrect.

Best from Tucson
Bob
 

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I know this is a long shot, but have you checked the fuel tank for a clogged vent line? Experienced similar running issues when my vent line got clogged, I just opened the fuel cap a turn and it solved the problem almost immediately. Had you just recently filled the fuel tank, like before riding it to work?
 

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Discussion Starter #11
thanks all for the suggestions. last night i decided to do a preliminary inspection so i pulled off the left side cover and checked the bike for vac leaks, made sure the injectors were plugged in and pulled the plugs out to have a look. what i found was #1 plug was coated and crusted a bit with oil and burnt on sludge. so because my local bmw dealers parts dept closes at 6pm i cleaned the plugs checked gap (best spec i could find was .034 +/-.007) and popped everything back together. now only cyl 1 was really bad. all the others were bad enough though. i took it for a ride and Viola! My bike was back to riding like a Bmw should. Now i know that this isnt solving a problem only a symptom, but its good enough for now just to know its not some weird electrical demon causing my poor running condition.

Lesson learned here, my cyl 1 is likely huffing a bit more oil than the rest. Dont park it cylinders down hill when using the sidestand.

oh and one last thing, I noticed when i had the cover off that there looked like an extra fuel injector plug on the bike right around where the fuel injectors were plugged in behind the LH fan. I didnt see anywhere to plug it in (and probably wouldnt have if i did) Is that some CA emmisions plug that is not used or a cold start injector plug for some other market?

Lastly Thank you all for your suggestions. Im sure this wont be the last time i look for guidance from this site.
 

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2005 K1200LT
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Carsucharda said:
oh and one last thing, I noticed when i had the cover off that there looked like an extra fuel injector plug on the bike right around where the fuel injectors were plugged in behind the LH fan. I didnt see anywhere to plug it in (and probably wouldnt have if i did) Is that some CA emmisions plug that is not used or a cold start injector plug for some other market?

Lastly Thank you all for your suggestions. Im sure this wont be the last time i look for guidance from this site.
That is most likely for the vent valve on the charcoal cannister line. Looks like your cannister has been removed.
 

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Discussion Starter #13
not surprised. I think i may have bought this bike from someone who also spent a lot of time on this forum.
 

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My brother bought a 2002 K1200RS with the identical engine - but with some extra HP - would hesitate as high speeds - replaced fuel filer - all is good. He could not blow through the old fuel filter. Do you have maintenance records if not you need to, as others have said, stick to some of the easy solutions and you most likely find the culprit!!
 
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