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Thread: Cold low speed pop back

  1. #1
    Junior Member Just broke my cherry!
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    Cold low speed pop back

    My 2007 road king with efi pops back thru the intake when I first start riding at low speed. After it warms up it runs fine. It's been maintained to HD specs. Any help would be appreciated.

  2. #2
    Administrator AdminSenior Member Wide's Avatar
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    Lean pop
    Most likely intake gaskets, very common when it gets cold, soon as it warms up they expand and seal

    Good luck
    .-/c-.,_ /
    (_)'==(_)

    "Logic will get you from A to B. Imagination will take you everywhere"

  3. #3
    Junior Member Just broke my cherry!
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    Thanks

    Thanks Wide I'll check that out.

  4. #4
    Administrator AdminSenior Member Wide's Avatar
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    Other thing it may be is just running a bit lean due to cold weather. If you never had the ECU mapped that may do it. If a carb them most likley gaskets
    .-/c-.,_ /
    (_)'==(_)

    "Logic will get you from A to B. Imagination will take you everywhere"

  5. #5
    HCG Technical HCG SupporterHCG TechnicalSenior Member
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    one of the things that is often left out of a ride is the start up. letting the bike idle for a bit before taking off not only allows the ecu to catch up, but also allows the engine components come to temp. we let ours go for at least 5 minutes (rocker covers too hot to keep your hand on). just a thought....

    j

  6. #6
    Administrator AdminSenior Member Wide's Avatar
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    Quote Originally Posted by junior View Post
    one of the things that is often left out of a ride is the start up. letting the bike idle for a bit before taking off not only allows the ecu to catch up, but also allows the engine components come to temp. we let ours go for at least 5 minutes (rocker covers too hot to keep your hand on). just a thought....

    j

    Merry Christmas!!!!!
    .-/c-.,_ /
    (_)'==(_)

    "Logic will get you from A to B. Imagination will take you everywhere"

  7. #7
    Junior Member Just broke my cherry!
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    Popping noises (and occasional misfires)

    Hi. I hope that someone is still reading this thread.
    I have a 2000 Road King, and I would get a lot of "popping" and occasional misfires when my bike is warming up, or idling.
    After reading some of the other posts in this group, I checked and tightened all four of my exhaust nuts down a good 1/2 turn.
    This reduced most of the "popping" and misfires. I sprayed WD-40 around the intake manifold seals with no noticeable change in symptoms.
    I dropped the carb, and cleaned the float bowl and the jets, but they were basically already clean.
    I replaced the spark plugs, the fuel line, and the inline fuel filter that I run, at the same time.
    I have 87,000 miles on this bike, and I had to park the bike outside last winter. (It was covered with a bike cover)
    Have any of you ever had any improvements when you replaced the plug wires?
    I know the "popping" and mis-fires are trying to tell me something, but I'm too naive to know what.
    Any suggestions?
    Sleepyjohn

  8. #8
    Administrator AdminSenior Member Wide's Avatar
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    Intake leaks is a big thing during cold start, pops if any leak at all
    .-/c-.,_ /
    (_)'==(_)

    "Logic will get you from A to B. Imagination will take you everywhere"

  9. #9
    Junior Member Just broke my cherry!
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    Cool Popping noises (and occasional misfires)

    THANK YOU, THANK YOU, THANK YOU!
    I LOVE YOU GUYS! (does not mean we are going to start dating)

    So I had a slow day today, so I pulled the carb, and removed my air intake manifold.
    The rubber seals were tightly pressed, but otherwise looked OK.
    Nonetheless; i had made it this far, so I tapped the locking rings free, and removed the old intake seals.
    Reading some of your previous posts (nah! I read them ALL!!!!!), I used a small wire brush and cleaned away any/all imperfections till that manifold was shiny clean.

    At this point, I noticed the "Manifold Absolute Pressure Sensor" that was mounted to the top of my intake manifold.
    The screw that holds the locking bracket in place was backed out about halfway, and the MAP Sensor wiggled A LOT.
    I disassembled the MAP Sensor from the manifold, checked the bracket and reassembled tightly.
    I checked it again; disassembled it, cleaned out all the fuel/oil/dirt drainage from around the Sensor hole,
    dropped a drop of red locktite in the screw hole, and reassembled the MAP Sensor and locking bracket to the manifold.
    It was rock solid! No wiggling, no looseness. Connected the cable back to the sensor.

    I wiped my new manifold seals with a light coat of motor oil, and reassembled everything.
    Once I was done, i started the bike to see if I had any more popping, or misfires, or anything abnormal.
    NOTHING!
    It runs like a new bike!

    I AM SOOOOO HAPPY!!!!!!!

    Last month, I did a run to Eastern North Carolina for Mother's Day.
    The bike ran sorta smooth, as long as I stayed on the throttle.
    If I let off on the throttle; the bike would misfire, or pop out the rear cylinder exhaust pipe.
    Turns out this MAP Sensor is closer to the rear cylinder intake.
    Two weeks ago, I drove to Nashville, and had the same symptoms: Ran great under throttle, but popped and misfired at idle or off-throttle.

    Now; This puppy is running SWEET!

    I'll run up to Virginia next week and see how she does!

    THANK YOU, THANK YOU, THANK YOU! You guys are the best!
    Sleepyjohn

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