BMW Twin MC
Air Bypass screw FI Setup
for smooooth cruise.

  1. Sync throttle bodies

    1. Absolute smoothness is directly related to perfect throttle body synchronization!

    2. Use mercury sticks or a 2 gauge setup. I prefer the mercury sticks as the mercury is not affected by knocks - as a gauge is likely to become out of spec if dropped or knocked. and you'll never even know..... Either is fine -

  2. Set Air Bypass screws.

    1. At this time">

       

      BMW Twin MC
      Air Bypass screw FI Setup
      for smooooth cruise.

      1. Sync throttle bodies

        1. Absolute smoothness is directly related to perfect throttle body synchronization!

        2. Use mercury sticks or a 2 gauge setup. I prefer the mercury sticks as the mercury is not affected by knocks - as a gauge is likely to become out of spec if dropped or knocked. and you'll never even know..... Either is fine -

      2. Set Air Bypass screws.

        1. At this time, set both at 2 complete 360 degree turns out from lightly bottomed out. That's call 2.0x.

      3. Install new chip.

        1. Start engine.

        2. Ride around a bit.

        3. Come back. 

        4. In neutral, start engine and bring rpm back up to 2800 rpm.

        5. Take a screwdriver and lean out the RH air bypass till the engine runs smoothest.

        6. Go ahead- be surprised....

      4. The suggested RH and LH 2x turns out on the Air Bypass screws  is a start and a proper tuner and / or a dedicated owner will be able to make it "best". 
        You might have to go to 3.0x or 1.5x on the LH for the best  cruise. Just slowly unscrew, in 1/8ish increments and listen to the exhaust "burfle" at 2800 rpm -  if it gets worse when you unscrew - go the other way! 
        What you are looking for is the smoothest running in neutral at 2800 rpm.
        You can do the RH Air Bypass screw after you do the LH.
        If you get lost and confused - stop - have a Coke and just start over - at 2 turns out on both sides. 
        Now - reattach the carb synch tool and resynch the throttle bodies - for a final synch -
        With no load on the engine at all, I'd be surprised if you could get it "silk smooth" in neutral, but - do the best you can.
        I think that there are some issues with all bikes as far as rpm scatter recognition at part throttle settings - from what I've seen in research on the new TEKA EMS FI box. Really common, it seems. The TEKA EMS actually conditions the ignition pulse BEFORE it gets to the ECU and actually settles things down - better than stock! Cool!

      5. Life is good (or at least better and smoother!)

      Any feedback that you can think of that might help - feel free to click here.

      We'll see how long this BMW page exists before it becomes common knowledge....... and people forget who wrote it down.......  Factory Pro - the guys who make real dynos with real, comparable hp numbers? Remember them?? The guys who tune more odd stuff than... The guys that figure out the weird, unprofitable stuff - because it's a challenge? 
      Great in Tech!
      Lousy in sales promotion!
      That's us!   :-)

      Oh - I did this with our chip and I don't know that it will work with a different chip, from what I've read in other maps that I've researched - There were a lot of changes in fuel, acc., timing and correction maps that I did - I spent probably 4 hours in the 2000 - 3500 rpm and 0% to 30% throttle range to figure it out - Give it a try, though - Just remember to count the number of turns out the air bypass screws are before you start.

      Also - "Things that DON'T work."
      Teclusion box - it is NOT what the BMW's need - it only has 2 ranges that work on throttle position only (not what you need) and acc. pump. and can only make things richer across the rpm band - Not able to target that 2500-3000 rpm / 5% to 20% throttle -
      I'm know that there's a number of bikes that could use that small, simple enrichment thingie, but, the BMW is not one of them, at all.
      If you are familiar with tuning, it affects the bike like a "Yosh" box for the Suzuki's, but, only has two ranges (instead of 3) and can only make things richer, (not leaner as the Yosh box for the Suzuki can - and is only referenced to throttle position - not rpm.

       

      Marty K. / R1100gs / Remus exhaust:

      Says that "It's almost perfect!" after his trip from Mill Valley to San Diego last weekend.
      Now, he says - if I could only fix the little "fuel bump" at closed throttle/2200 rpm..........  Maybe some day - at least I already know what it is. Heck Marty - one miracle at a time!!

      OK - so - now, if you think you can "throw" a chip in and expect miracles - it might happen - but, contrary to public knowledge, you DO have to do some tuning to adjust the chip's mixture to match your bike!
      That's true of BMW, Ducati, Aprilia and Guzzi. That's why I always prefer to custom tune each BMW - it's worth it.

      Cheers and all that!

      Marc