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85 BMW K100LT

Discussion in 'Other Motorcycles' started by Timbox, Oct 30, 2020.

  1. Steve Otto

    Steve Otto New Member

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    Does yours not have the air meter(flapper box)? If it does, make sure its lubed and able to move freely. Mine would stick causing surging and bogging depending on the position. I think I used PB blaster and (spray) lithium grease to free it up.
     
  2. Timbox

    Timbox Well-Known Member

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    Steve again, good advice. I see off the brick sight they so don't adjust it. I will get some new injectors today, seal up the vacuum nipples and maybe get a K&N filter. This will be a run to town bike anyway, just something that fell into my lap.

    Need to take are of the rear foot break light swx as well. Was pulled apart and I had to solder wires back to it. Had it working on the bench and now that it is in place, does not work. Temps are dropping again, that doesn't help.
     
    Last edited: Mar 12, 2021
  3. Steve Otto

    Steve Otto New Member

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    That’s strange about your rear brake switch since they’re such a simple design. If the switch bench checked ok, double check the wire resistance. Im from the mid-west (Michigan) too and always found corroded or burnt wires where I wouldn’t expect to on bikes and snowmobiles.
     
  4. Timbox

    Timbox Well-Known Member

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    Steve,
    The wires were stripped away from the sxt and only the ears on the swx were left. I soldered new wires on and bench tested it, worked fine. I am sure it is something simple like over tightned it or something. Life is getting in the way today, so I hope Sun I can get back to it. New Ford injectors on the way and the new versions as well.

    Have you ever heard any good/bad about going to a Full slip on K&N filter and removing the air box off these bikes. Just looking at that for an option. I know these bikes run rich anyway.
     
  5. Steve Otto

    Steve Otto New Member

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    Because of the intake design on the K-series, putting a pod or cone filter on will either be expensive (or time consuming to build) or just look goofy. Since the intake plenum points straight out to the side it limits the size of any filter you could put on. Likewise the attachment of a filter to the “flapper box” would need a special adapter with a tight 90* elbow. If you are just using it as a run to town bike, I don’t think switching it would make noticeable difference to justify the time, money or effort. That said, a stock fitting reusable high flow filter (K&N) wouldn’t be a bad choice since you only need to buy it once. Just my $.02.
     
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  6. Timbox

    Timbox Well-Known Member

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    I think most of the folks just put a cone K&N filter on the 90 degree that connects to the stock air box. That was all that I was thinking of doing. I will wait to see how she runs with the new injectors and go from there. Cold snap coming and a little more snow here so, on pause for riding her.
     
  7. Timbox

    Timbox Well-Known Member

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    Bike started right up even in cold temps. Still waiting on the new FI's to show up. This bike does not spool up too fast, might be just the model K100 its self. We will see when I change out the Injectors and maybe the plugs.
     
  8. Steve Otto

    Steve Otto New Member

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    You could always stuff a rag in to restrict air flow, if it spins up faster it’ll confirm fuel starvation. You said earlier it was getting pretty hot running so you should be pretty happy with the new injections. I did it to my k75 and an old Jeep both had good results. Smoother idle, better mileage, and my seat dyno indicated more power
     
  9. Timbox

    Timbox Well-Known Member

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    Steve, that is great news. The injectors came in last night, hope to get here done today and out for a test ride. I will be keeping this bike as the FI system is so easy to keep up and not worry about the spring carb thing. I do like to have a little performance but I know that this model is not a performance bike from factory. A K&N will be next and I also want to do something about that nasty stock exhaust sticking past the back tire. It has 4 single headers coming out to a collector and I need to see where the O2 sniffer plugs in as well. I would like to have that single sided swing arm a little more eye catching. I would also like to have it sound a little better. Does not have to sound loud or evil, just a little something.
     
  10. Steve Otto

    Steve Otto New Member

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    I’m about 99% sure that unless you have a euro spec model, K-100s don't have an O2 sensor. The 1100’s did but not the 100’s or 75’s they just use atmospheric pressure and airflow to adjust to “pretty good” emissions.
     
  11. Timbox

    Timbox Well-Known Member

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    Cool good to know about the O2 sensor. Changed aout the FI's today, easy for the most part with minimal gas spillage. Bike does run much better and I think with a little more running it will get more responsive. There could be some pits in the gas tank too, so might have to take the injectors off again and do a quick fuel flush of the lines. New injectors have 4 nozzle on them, nice.
     
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  12. Timbox

    Timbox Well-Known Member

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    This bike found a new home today. I hope the new owner is happy and takes good care of here. I would bet that she will be sold as a flip project in a bigger city. Nice kids that picked her up.. One is a Army ROTC so I wished him well in his future.
     

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