need some tunning help

Discussion in 'Sportster Models' started by ashenfang, Sep 10, 2008.

  1. ashenfang

    ashenfang Member

    Okay, finally was able to get the bike out on some highway riding. I am running the TFI with stock air box and rush slip on's.

    1st through 3rd gear has good power, good accel., now when I get into 4th, I can't drop below 40 or she starts to bog, but 4th is good up to almost 55mph or so. Now, when shifting in to 5th at 50-55mph, its almost like the bike "bogs", and giving more throttle results in very slow acceleration with that bogging-slapping sound from the exhaust. There is some heavy vibration associated with this as well. Now, one you let off the throttle and cruise, it doesn't feel bad, but still not right.

    So....where does the problem sit? I spoke with george a few days ago and really just asked him one question which was "what pot cruise is fed from" and he said pot one. But now I am thinking though that in high gears and higher speeds, cruise may be fed from a mix of pot1 and pot2 ???

    My current settings are 2:30 - 2:30 - 2:30 - 4:30

    Now the TFI can not subtract fuel, correct? Meaning, regardless of how low you set it, it will never be leaner than stock?

    How does the open loop system affecting anything since the O2 sensors are no longer used?

    Any help appreciated!
  2. glider

    glider Veteran Member

    It sounds more like you are lugging the engine than fuel mixture judging by your statement " bogging-slapping sound". Remember that you added fuel to the mix so the engine characteristics will change some (ie. more power) so your driving habits will no doubt change a bit too.

    The TFI is delivering fuel according to RPM of the motor, not speed of the bike.

    The #1 pot is low speed and the #2 pot is the accel pump feature. I would lower the #2 pot and test it out doing that to reduce fuel delivery if you feel it is rich. I usually run the #2 pot very low.

    You are also correct that the TFI will not run any leaner than the ECM map.