engine surging?

Discussion in 'Sportster Models' started by FRANKENCHOKY, Dec 23, 2007.

  1. FRANKENCHOKY

    FRANKENCHOKY Member

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    i just did my 1000 mile service and the hd dealer said my scoot was surging at cruising speeds.
    the mechanic said he couldnt find anything wrong but wants to still look into it. i took the bike home to test ride it to see what they were talking about.
    to back track a little bit i noticed this surging the first day i got it and took it in to have them check it out. this is my first hd so i didnt know what is normal or not. they said it was probably the primary chain and that they would check it out on the 1000 mile service. now i do the service and there telling me theres a problem but they dont know what. the mechanic is checking in to it.
    does anyone know what might me going on?
    during the service i had them install the s/e air filter kit and remap. now the bike runs smooth as hell except the surging.
    the surging is noticable at part throttle or when im on the freeway staying at the same speed. the higher the rpm the less noticable it is. more so below 20mph. it kinda made taking my motorcycle driven test a little hard. i had to take the test riding the clutch.:bigsmiley31:
     
  2. glider

    glider Veteran Member

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    A few possibilities are wrong map installed, damage to the manifold boots when they installed the Stage 1.

    Ask them to upgrade the map to the race map for that bike, (richer). Bet they tell you they don't know what you are talking about.
     
  3. FRANKENCHOKY

    FRANKENCHOKY Member

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    the bike has done this from day one. and it still does this now with the new map.
    :cry
     
  4. glider

    glider Veteran Member

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    Sporties are very cold blooded and need some fuel to run right.

    Take a look here and try this to check for an intake leak. It definitely sounds like a lean surge, what if you down shifted to the next lower gear, would it still do it?

    Finding An Intake Leak - Harley Davidson Community

    Also check for any disconnected or cracked vacuum lines which would lean it out and cause this condition.
     
  5. glider

    glider Veteran Member

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    One thing I found on the sporty is to shim the needle up with 2 #4 brass washers to raise it a bit and it helps over come this problem on carbed models. The fuel delivery is started earlier in the cycle when the slide starts to lift.
     
  6. FRANKENCHOKY

    FRANKENCHOKY Member

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    ill do the check for a leak but the bike does it all the time. warm,... cold. that doesnt seem to effect it. if im putting from one stop light to the next in first or second gear. it does it. like when i had to weave in and out of the cones for my drivers test. or if im on the freeway cruising at a lower rpm it does it.
    if i give it a bit more throttle and raise the rpms it goes away and the bike runs awsome.
    its not a big surge. i can feel it more than i can hear it.
    like the bike is pushing and pulling if that makes any sence.

    if i seem like im repeating myself im not trying to. i guess im just trying to describe what happening as best i can.
    i do apreciate the help.:skipping
     
  7. glider

    glider Veteran Member

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    The main thing that causes surging is a lean mixture either from an intake leak or a lean mapping on a FI bike. On a carb bike it's jetting or intake leak.

    The part that you mention about it happens at a lower RPM, if it is below about 1200-1400 RPM, it may indicate a loose primary chain.
     
  8. FRANKENCHOKY

    FRANKENCHOKY Member

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    ok,...so my hd mechanic is off on vacation but he called me and said that he found a service bulletin about there being a problem with the fuel regulator. once he gets back hes going to check that out and see if thats my problem.:coffee