Strange "surge" at low speed.

Discussion in 'Other Service and Maintenance' started by oldjarhead, Jan 25, 2010.

  1. oldjarhead

    oldjarhead Member

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    I've had a few occaisions, when down shifting to first at low speed, the engine rpm will surge and the bike will lunge forward while the clutch is compressed. Anybody else have this and how to fix?
     
  2. BOBFLHTC

    BOBFLHTC Active Member

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    Is it possible you have the handlebars turned to one side ?

    Happens when I back out of the garage and I am turning around. The throttle cable seems to bind.
     
  3. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Check these out:

    EFI Engine Surge - Harley Davidson Community

    TQ
     
  4. Chopper

    Chopper Senior Member

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    Not sure if I fully understand the question but the new electronic's on the EFI bikes, a signal is sent to the ECM on rear wheel speed and will sometimes keep the engine rpm's up longer then a carb bike, a little unnatural, maybe could cause a slight surge on the road, depending on how you downshift and rpm range? Being a X police bike I know they are hard on clutch's, could it be excessive clutch wear? I've heard complanats from newer dyna owners that cruising at 10-15 mph they experience engine surging, drive them crazy, in 06 I upgraded to the new injectors on a bike but only thing seemed to make any change was building a custom fuel map on the dyno. I think part was due to lugging.
     
  5. oldjarhead

    oldjarhead Member

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    some more info, happens most when coming to a straight line stop and some when manuvering in parking lots (spooky!!) bike does have ABS. Clutch seems OK adjusted right cables lubed and so on. This just baffels me. As an old jarhead ('75-'70) and old machinist (25+yrs.) it bugs me when I can't figure something out.
     
  6. Chopper

    Chopper Senior Member

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    Times are flying by, did they have ABS in 05, maybe was first year special order on pd bikes. I'm sure you know this, but ABS brakes do pulse when applied. What mods does the bike have? I'll go back thru my HD bulletins & tech tips to see if I can find anything that might apply.
     
  7. oldjarhead

    oldjarhead Member

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    It's pretty basic, stage one, screamin eagle air cleaner, Vance & Hines slip ons. Thats about it.
    As far as the ABS, it's noticable alot in traffic so I'm familliar with it. I think it was a special ting on some police bikes that year. The module looks like it belongs on a truckk and eats up about 1/4 of the right bag. The surge is pretty dtrong at times and overpowers the brakes to try to accelerate.
     
  8. Chopper

    Chopper Senior Member

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    Does just have a HD download, sert or a type of fueler on it do you know? Also any trouble codes? What do the plugs look like, I would throw a new set in if they haven't been replaced for a while.