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Thread: Hard Start

  1. #1
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    I am sure the answer will be TPS reset. Had my pipe gutted, left the exhaust valve it. Sounds great, little loss of power in low end but I can live with that. Seems to "miss/sputter" intermittently at low RPMs. Then, a few days ago, would take a few attempts before bike would start. Once started, idled fine. Still has the intermittent "miss/sputter". Still has stock ECU, was told that as long as I did not modify airbox, stock ECU can compensate and not run lean.

  2. #2
    Senior Member
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    Run 10-20 minutes at around 3500RPM to relearn the ECM. It might fix it...

  3. #3
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    Have you done the Breather rerout.

  4. #4
    Junior Member
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    Sep 2008
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    I have not done the breather mod. Also, seems to be worse when it is cold, more so than before the mod. I don't ride the bike hard and was told the race ecm only changes the fuel mapping for higher rpms.

    For the relearn, are the 3500 rpms in neutral or on the road and do you have to start over if the rpms drop below 3500?

  5. #5
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    The breather mod will help a lot. The ECM running in closed loop will not help a lean problem it just adjusts to the conditions your in ie. Humidity or lack of, altitude . If its lean the only way to change that is a Race ECM, a EFI controller like Dobeck or Remus power commander or use mapping software like ECMspy or your dealer can change your fuel maps. Vtwins have a hard time starting in the cold so thats not uncommon, if its real bad make sure you use the motor oil recommended for your starting temps.

    For cold weather starts

    H-D Multi-grade
    SAE 10W40
    HD 360
    Below 40° F (4° C)
    Excellent

    H-D Multi-grade
    SAE 20W50
    HD 360
    Above 40° F (4° C)
    Good

    H-D Regular Heavy
    SAE 50
    HD 360
    Above 60° F (16° C)
    Poor

    H-D Extra Heavy
    SAE 60
    HD 360
    Above 80° F (27° C)
    Poor

  6. #6
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    Were in Florida, so it really does not get that cold. Want to stay away from the race ecm as I believe that will really only help at higher rpms. I have heard good things about TFI Techlussion and Remus so may go that route. I am afraid that if I try ECM spy, I would mess it up. What does the TPS reset actually accomplish? I am curious as to how changing a pipe or adding a module could change that.

  7. #7
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    Im in Florida too, Central Florida. The TPS reset only readjusts the position of the throttle in relation to the rpm so the ECM knows how much fuel it needs to be putting into each cylinder as you twist. When you change a pipe or a high flow filter your adding more air to the equation changing your idle rpms. Your idle rpm and throttle position is your base from where your ECM makes all its calculations, if thats off everything after that will be off also. Your basically just synchronizing your throttle, idle and ecm so there all on the same page.

  8. #8
    Senior Member
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    Quote Originally Posted by gijimbo1313
    I am sure the answer will be TPS reset. Had my pipe gutted, left the exhaust valve it. Sounds great, little loss of power in low end but I can live with that. Seems to "miss/sputter" intermittently at low RPMs. Then, a few days ago, would take a few attempts before bike would start. Once started, idled fine. Still has the intermittent "miss/sputter". Still has stock ECU, was told that as long as I did not modify airbox, stock ECU can compensate and not run lean.
    - you need a reset before your ecm can compensate, unless you have an '08 en up.
    - your ecm will still run lean, since it runs lean from factory, it will only get worse with a gutted pipe.

    but...your problem could also be a battery/ignition thing.
    if your battery is nearing its end, your ignition is weak and will give you a bad burn.

  9. #9
    Junior Member
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    Sep 2008
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    Are we talking dangerous lean as in damging valves, piston, and plugs? I have pulled the plugs and they appear light tan....not sure how much tan was there before the mod.

  10. #10
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    i'm not saying your engine will fall apart tomorrow but it isn't thge healthy thing...

    how healthy depends on how lean ;)



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