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Help! my bike won't electric start - starter relay or motor?

Discussion in 'Technical and Troubleshooting Torque' started by ragedmachine, Jan 22, 2010.

  1. #1 ragedmachine, Jan 22, 2010
    Last edited by a moderator: Jul 13, 2015
    Ok here's the story:

    - Bought a KTM LC4 640 about a year ago, the electric button start used to work (groggy at times) but eventually it died and wouldn't start from the button.
    - I've since used the kick start with no problems, but now since the weather is bastard hot, I'd like the luxury of just pressing the button to start.
    - I replaced the battery recently thinking it would solve the issue, but still nothing changed.

    So at the moment, when I try to press the button, there is only a 'click' coming from the starter relay. I tried bridging the two points with a screwdriver, but same s*** happens.

    I'm trying to decipher if it is the starter relay or the starter motor that is the problem, I'm leaning toward the starter motor because the at least the starter relay gets a response when I press the button!

    Here's a short vid to describe what I'm on about:


    Can anyone shed any light as to what could it be?
  2. I haven't looked at the vid (damn work proxy) but the solenoid could be jammed. Try giving it a good ol thump or two on the outer case to see if you can free it up.
  3. Possibly Battery charge/age sometimes if the voltage is low its enough to pull the solenoid on but not close the heavy current circuit to get the Starter motor spinning. With a multimeter check the battery voltage when you press the button to start. It will drop but shouldn't go under 10volts.
  4. Try running heavy cables direct from the battery terminals to the starter motor terminals (expect sparks when contact is made. If the motor spins, your problem is in the relay or wiring, if it doesn't, it's the starter motor. Easy.

    If it is the starter motor, it's probably the brushes. Take them out and take them to your local auto electrical supplier but avoid telling them what they're for. I'd guess KTMs use Bosch electrics and, if you're lucky, you'll be able to use a standard, Bosch part without having to pay KTM spares prices.
  5. Thanks, but I bought a new battery and even charged it overnight to see if it was but obviously not!

    Great, I will try directing connecting, and inspect bushes if it doesn't react!

    Just on this note - as I've been starting/riding fine by kick-starting, I'm assuming the starter motor hasn't got anything to do with the kickstart?
  6. Nope. Generally two entirely separate mechanisms. Kicksart works through the gearbox. Most starter motors that I've seen operate directly to the crank or via the primary drive.

    BTW, when you try hooking up the leads, as I said expect sparks. Make sure that you do the last connection at the starter motor end in order to keep those sparks well away from the battery.
  7. Ditto everything from PatB.
    ALSO make sure of polarity (+ and -) before yoou connect the wires or you'll get BIG sp:cry:arks
  8. motorcycle starters are permanently engaged, unlike cars where the solenoid 'throws' the pinion at the ring gear ?????

    the fact that this was a slowly degrading issue points to some electrical gremlin, rather than mechanical, though...