Weird electrical gremlin!!

Discussion in 'Sportster Models' started by lrburke, Mar 20, 2011.

  1. lrburke

    lrburke New Member

    Hi there fellow Harley riders, I am brand new to this forum. I have a 1988 sportster 1200 and a week after I got it this happened!! The starting system worked normally by turning the on/off switch to run and the key to on and then pushing the start button. Just like it's designed well now all the sudden the bike starts when I turn the key on. I think the starter is still spinning when it's running so I turned it off immediately. The first time it happened it startled me so bad I almost dropped the bike over on me!! I am capable of figuring it out but just need a wiring diagram or some good advice. I will appreciate either. Thanks a bunch!
  2. ultra...good

    ultra...good Banned

    I would start by checking the start button, sounds like it is stuck.
  3. TripleJ

    TripleJ Senior Member

    While I cannot help with the wiring diagram, it sounds like the start button is the place to start.

    Try this, make sure the on/off switch is off first, then turn the ignition switch on , then turn the on/off switch to on and see if it still starts on its own. If it does not automatically start until you flip the on/off switch to on the problem is most likely the start button or circuit is not disengaging.

    And welcome the the forum!

    Looks like I was to slow again :)
  4. lrburke

    lrburke New Member

    Thanks for all the quick replies. I will track down a diagram and see what I can figure out. I will post back in a couple days. Thanks a bunch.
  5. JBC2565

    JBC2565 Junior Member

    Welcome to the forum lrburke. Grew up in Loveland OH.
    A Harley service manual is a must have for your bike. It will let you get to know your bike better and save you a bunch of money. Can find them on e-bay for less money than the dealer wants for them.
    Great tips in self help section or ask the forum.
  6. W1ld Card

    W1ld Card Member

    A diagram probably isn't really needed. It's very simple, really. The ignition switch (the key-hole) gives power to the starter button. The starter button gives power to a solenoid. The solenoid gives power to the starter motor. When you press the starter button, it closes the connection in the switch, which then closes the circuit, and transmits the power from the ignition to the starter solenoid. When the starter solenoid gets that power, an electromagnet magnetizes, and closes an internal circuit in the solenoid. At one side of the circuit is the battery, at the other end is the starter motor. When the internal circuit is closed, the starter will run.

    So, if the bike is constantly starting when you turn the key on, your switch is bad (stuck in a closed circuit). You can take the handlbar controls apart, and trace the two wires from the starter switch. Then, take a multimeter, set it in continuity mode, and see if those two wires are "open" (no continuity, AKA, no connection) or "closed" (continuity, a connection is being made between them, AKA the switch is stuck internally).

    If the two wires are showing continuity, well, your switch is stuck. Odds are good you'll have to replace it, but maybe getting a tiny bit of oil into the switch and then tapping on it while you work it back and forth might get it to free-up inside.

    I really feel this is the only feasible possibility.


    edit: Or, you got water in the switch. That could be "closing" the circuit, too. If it still acts this way after trying to tap and work it, maybe stick a blow-dryer on it for a couple of minutes. That should evaporate any water inside.