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80"Shovelhead problem causing bike to cut out while riding. PLEASE READ.


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  • 80"Shovelhead problem causing bike to cut out while riding. PLEASE READ.

    Hello all.

    Helping a friend with a problem hes got. He came to me stating that he cant ride his bike because it cuts out while he is riding it and asked me to help him out to track down the problem. I (think) i have checked over every inch of this bike and cant solve the issue.

    Its an 80" shovelhead, all stock componants besides dyna S ignition and an after market wiring harness.

    I picked up the bike from him and brought it back to my house, took it for a test ride and it died basically as i left my driveway. Rode it around for a while trying to pin point a pattern to see if i can figure out why and when its occuring, high rpm, low rpm etc.

    Riding the bike and the bike cuts out, It stays running (idling kind of) and if you twist the throttle you can hear it still squirting fuel. The bike will continue to idle down the road basically until you pull in the clutch and the the engine cuts out completely. While still rolling, you can hit the starter buttom and it will fire up and you can ride along till it dies again.

    it will do this at high rpm, low rpm, it has done it while i was getting on it and it has done it while i was backed off turning a corner. I cant find a pattern to the problem.

    I have run diagnostics on everything and replaced anything that was needed. Also completely re wired the whole bike cause it was a mess and put a brand new CV carb on it.

    I have checked battery voltage, ohm and resistance of the stator, replaced coils check all connections of everything, check the E. ignition, I have rewired the ignition to be on its only little circuit so that it didnt run through the aftermarket brain at all and still dies.

    I have check the regulator as well and at first seemed checked out fine but then checked it again today and with the bike around 2000 rpm only crept up to about 14 volts.

    Have I missed something? The only thing i can think of if the brain has a fault and is doing something.. But i cant run diagnostics on it to know for sure.

    Any help or info is appreciated. Im sick of working on this thing and want it out of my garage and down the road.

    What kinda problem does it sound like to you?


  • #2
    Substitute a known good set of points and see if the problem persists.
    What is that you keep referring to as a "brain"?
    Does the bike loose all electrical power like lights, horn, brake etc?
    Or does it just run really bad and quit running?
    What is the battery state of health?
    Charging system AC Volts output results?


    • #3
      Toss in a good quality points ignition to eliminate that variable and continue if needed. Tune with this ignition and see how it runs, then if you must, replace it with a new electronic once confirmed everything else is cherry.

      Looks like I was too slow. Lol


      • #4
        Originally posted by JAWS
        Looks like I was too slow. Lol

        LOL Like always my friend.......LOL


        • #5
          replace your ignition module or go to points , I kno u have aftermarket brain as u call it but ive seen a ton of these do that bullshit, you replaced the coils so il rule out bad coil


          • #6
            That was my next thought. Pull the points out of my shovelhead and see what happens i ran the tests on the E.ignition as described online and didnt show any issues but i need to rule it out to be sure. good idea.

            This bike has a wiring kit in it that routes everything to a "brain" which controls everything. so once the bike starts the brain turns on the lights, runs blinkers, alarm etc.

            when it happens the bike stays running like an idle but you twist the throttle and there is no spark or something.

            battery is brand new and showing correct voltage.


            • #7
              Bypass that alarm thing. Wire it simple simon style and put him in the wind.


              • #8
                Can be so many things , hard to halp on.line , I meen after reading that post sounds like idle port jet clogged then I read more and me thinks teh brain is fucked,
                Id guy that fucker and rewire it and try dem points


                • #9
                  I agree many things can cause this problem once it was my module or brain as u call it that caused it to cut out! And another time it was something as simple as intake manifold band rubbers dry rotted and cracked sometimes there's cracks not visible in old rubbers and other times they fall apart when the manifold is removed! But like Davetune said could be alot of things! One time it was a bad circuit breaker got hot cut out! Also a short can cause this! If u hear it click and starts back up breaker or short!


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