Coming full-circle... Solo Lobo's next project - 1984 R100RS

Discussion in 'Airheads' started by Solo Lobo, Feb 28, 2018.

  1. Airhead Wrangler

    Airhead Wrangler Long timer

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    Back in Seattle, FINALLY
    Sure hope it works
    Solo Lobo likes this.
  2. Dreem Ride

    Dreem Ride Adventurer Supporter

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    Dec 5, 2016
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    52
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    Seattle, WA
    Hey Solo,
    It looks like we're practically neighbors! We should get out for a ride sometime. Also, if it's not the hall sender or ignition module, I have a spare coil you are welcome to try.
    Solo Lobo likes this.
  3. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    Thanks, and I haven't considered a foot pad yet, that being said the only time I use a side stand is when there is zero possibility the center stand won't work, the there is a good chance the mike might fall over if left on the center stand.
  4. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    To be completely honest, I knew that when I called the problem as being a failed bean can I was just guessing... perhaps not a good guess at all. The only thing that was certain was that spark was absent.

    Pulled the tank today and checked the connections, other than one coil connection feeling a little bit loose (which I ignored) all appeared to be good


    [​IMG]


    [​IMG]


    [​IMG]

    So I moved on, disconnecting the battery and exposing the current "bad" can

    [​IMG]

    Rebuilt can on the right

    [​IMG]

    Tossed it in, fired up the bike, set the timing and enjoyed listening to it running

    [​IMG]

    And it sounded great

    <iframe frameborder="0" scrolling="no" width="360" height="640" src=""></iframe>

    Then I put the bike back together, tightened the tank retainer plastic thumb screws down, installed the tool tray and shut the seat. About an hour later I was wondering if the new can would be producing a better spark (did I mention the old can threw a spark today before I jumped in, because it certainly did... which I figured was just a minor reversal of failure)....

    Long story short, the spark went missing again... I have to guess my the issue with the RS is a connection, and not a can. No more time today
  5. ME 109

    ME 109 Long timer Supporter

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    Check the brown ground wire going to the left coil, if that connection fails there will be no spark.
  6. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    I'm running Dyna coils, and the brown wire is terminated in a ring terminal that is secured to the coil bracket where it connects to the frame.
  7. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    So, I found a few minutes.

    I pulled the tank again, and giggled wires, checking for spark each time I messed with a connection. Nothing

    Pulled the front cover checked the bean can connection, giggled that one, tested again and nothing. Giggled, pulled and pushed on the bean can to harness wire nothing.

    Waited a few, tried and again and found spark and the bike started right up.

    I need to do a thorough wiring and connection check of the ignition circuit.

    As the issue is unchanged with two bean cans (of unknown goodness), I'll start with connections, and check on the brown wire issue ME notes above.

    Somewhere I have seen a Dyna Airhead coil wiring diagram, but need to run now, perhaps tomorrow.
    ME 109 likes this.
  8. ME 109

    ME 109 Long timer Supporter

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    That ground wire should ground through the bolt threads at least, but prolly won't give an intermittent fail.
    I know the ignition will fail if this wire loses contact. Happened to me when my left coil mount broke, taking the ground with it.
  9. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    It seems like something is loose and making intermittent contact... I was hoping giggling wires would provide an easy diagnosis but no luck.

    Time for a more comprehensive deep-dive
  10. Dreem Ride

    Dreem Ride Adventurer Supporter

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    Might be worth pulling apart the kill switch on the handlebar. There's a set of contacts in there that interrupts power to the coil.
  11. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    If nothing else I found this missing piece when shuffling bikes around. Not sure if I will keep the current new thowout assembly in there or swap out for the original that worked just fine...

    [​IMG]

    So I studied the RS wiring diagram for a while, and pulled the tank again. I figured I would check each of the eight connection points for the ignition wiring and see if there was a definitive smoking gun

    What I found is that all four of the screws that hold the male wiring terminals to the coils were loose, "not flopping around loose" mind you but definitely "that screw is not tight" loose.

    [​IMG]

    And there was this, this was the first one I pulled and it was the worst by far... it was the 12v supply to the coils

    [​IMG]

    Cleaned it up plus the three others and reassembled, making each screw with tight, with a capital "T"

    [​IMG]


    I also disconnected the three other multi-wire connections, clean the terminals and having spark (which did look stronger to my eye) reassembled the bike again.

    No time to test-ride for a few days at least...

    No smoking gun found, but some interesting finds none the less
    mbanzi likes this.
  12. bmwrench

    bmwrench Long timer

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    6,669
    If you have all the parts to use the old clutch release bearing, I'd use it. I never had one of those fail, while the new-style has been a lot of trouble.
    Jim Day and Solo Lobo like this.
  13. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    Thanks for the advice, I do have all the parts and will toss ‘em back in
  14. Dreem Ride

    Dreem Ride Adventurer Supporter

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    Looks like those terminals would be easy to short on the coil mounting post/hardware. Other than the issue you just experienced, are you happy with the coil? I've been thinking about getting one, either the blue 0.7 Ohm or the brown 1.5 Ohm that you have.
  15. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    I’ve only done about 300 miles on this RS since I both bought it and refreshed the top end, so i don’t have any real thoughts on the coil performance.

    I’m also not sure how you would observe a difference between the 0.7’s and 1.5’s.
  16. Plaka

    Plaka Brevis illi vita est

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    The bean can is easy to test, but you do need the front cover off and the motor turning over on the starter.

    did you pull the spark plug wires out of the coils and look down the holes in the coil?
  17. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    The innards of the coils are clean... do you mean looking for something else?
  18. Plaka

    Plaka Brevis illi vita est

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    no.
  19. UnclePete

    UnclePete Been here awhile Supporter

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    Heat sink paste ?
  20. Plaka

    Plaka Brevis illi vita est

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    Better have fresh heat sink paste under the ignition module. Keeps it from over heating and screwing up. I redo mine yearly.