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Thread: 1985 K100RS non-start

  1. #1

    1985 K100RS non-start

    Hi Guys,

    Just changed the engine oil on my new to me 18,000 mile 1985 K100RS. Started up just fine. Got my gear and went to start for ride to heat up gearbox and final drive oil for changing as well. Dead. Starter switch does nothing. As in inert. Pulled battery, charged it. 13.3V Put it back in this morning. Starter switch does nothing. Kill switch turns off digital functions on dash so I don't think that's it. Plenty of gas. After starting attempts battery is 13.1V. Fuses all good.

    Is this a common issue, like a specific relay? Fuel pump gone bad?

    Thanks
    Steve

  2. #2
    Quote Originally Posted by stevenm View Post
    Hi Guys,

    Just changed the engine oil on my new to me 18,000 mile 1985 K100RS. Started up just fine. Got my gear and went to start for ride to heat up gearbox and final drive oil for changing as well. Dead. Starter switch does nothing. As in inert. Pulled battery, charged it. 13.3V Put it back in this morning. Starter switch does nothing. Kill switch turns off digital functions on dash so I don't think that's it. Plenty of gas. After starting attempts battery is 13.1V. Fuses all good.

    Is this a common issue, like a specific relay? Fuel pump gone bad?

    Thanks
    Steve
    I think a broken connector in the battery. Attach a volt meter. Read voltage key off. The voltage with the key on. Then the voltage with the starter button depressed.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://web.bigbend.net/~glaves/

  3. #3
    Battery at rest: 13.22V, ignition switch on: 13.18V, starter depressed: 13.18V

  4. #4
    Quote Originally Posted by stevenm View Post
    Battery at rest: 13.22V, ignition switch on: 13.18V, starter depressed: 13.18V
    Well, I was wrong. Something else is amiss. It sounds like a defect in the starter circuit. You should try cleaning the starter switch. If that doesn't fix it you will need to check for voltage to the starter switch and then for voltage from the switch to the starter relay. And then next of course from the battery to the relay and from the relay to the starter.

    The starter relay is located in the left rear corner of the relay box beneath the very rear of the fuel tank. It is the one with two visible wires attached with studs and nuts to the relay.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://web.bigbend.net/~glaves/

  5. #5
    3 Red Bricks
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    Quote Originally Posted by PGlaves View Post

    The starter relay is located in the left rear corner of the relay box beneath the very rear of the fuel tank. It is the one with two visible wires attached with studs and nuts to the relay.

    RIGHT rear corner.



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  6. #6
    A little intimidated by depressurizing the fuel injection system before taking the fuel tank off. Never had to deal with this with my trusty airhead.

    Concerned about fire, of course.

  7. #7
    Quote Originally Posted by 98lee View Post
    RIGHT rear corner.



    Oh boy. I knew that. Apparently I had a bit of "your other left" brain fade.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://web.bigbend.net/~glaves/

  8. #8
    Well, I traced the problem down, some time ago, and thought I would pass on info. It was the ignition switch. Took it apart, not the barrel just the switch itself and discovered a missing spring, probably when manufactured. Took apart a spare switch from my R65, replaced the missing spring, cleaned, lubed, re-soldered the connections, reassembled the switch, and voila, started right up. Just goes to show that the smallest thing can wreak havoc...

    Steve

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