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Testing Ignition Coil

Discussion in 'Motorcycle Tech Talk' started by heebeha, Nov 1, 2007.

  1. heebeha

    heebeha New Member

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    Anybody know how to test an ignition coil? I think mine is bad. I am getting a low spark sometimes, sometime no spark at all. Its shut down my bike a few times while driving.

    Also, when I turn the bike on and put the on switch on it pushes a spark to the plugs before I hit the starter button. That does not seem right. Is that normal?

    Its a 1981 Shovel 80ci

    Thanks
    heebeha, Nov 1, 2007
    #1
  3. chucktx

    chucktx Moderator Staff Member

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    i usually get my ol'lady to hang on to the wires for me........;)

    ground the plug, attach the wire, spin the bike over,,,should be blue spark, if not weak fire.
    if ya got points i have seen this happen quite often,,,,not a problem.
    chucktx, Nov 1, 2007
    #2
  4. 2fastnaz

    2fastnaz Moderator

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    dirty points or a weak condenser and bad plug wires would cause those issues as well.
    2fastnaz, Nov 1, 2007
    #3
  5. hotroadking

    hotroadking Super Moderator Staff Member

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    One of the ignition companies, crane, dyna etc makes a conversion kit for your bike to electronic ignition, FWIW I'd look into one of those kits, elimnate the points and condensor setup, put it aside for restoration and originality but if you're gonna ride this thing, switch to an electronic ignition.

    Solid state circuits will make it run better and smoother and its reliability in that area will improve. then you can work on all the other shovel issues you'll have :witsend: :gah: :roflmao:
    hotroadking, Nov 1, 2007
    #4
  6. heebeha

    heebeha New Member

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    I will check on it tonight

    Thanks. It seems that after the bike gets warmed up the spark fails. I wonder if a wire or something rumbles off. I have tested it after it shuts down and it does not get spark until I mess with the coil.

    Any feedback as to if I am supposed to get spark as soon as I turn the switch on? As I said I get a spark before I hit the ignite button to the starter.


    I will check on a conversion kit and try cleaning my points after I find out where they are. Hummm
    heebeha, Nov 1, 2007
    #5
  7. ringo912

    ringo912 Active Member

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    You usually get the ol'lady to hang onto the wires for you :roflmao: Your killing me Chuck.:roflmao: :roflmao: :roflmao:
    ringo912, Nov 1, 2007
    #6
  8. chucktx

    chucktx Moderator Staff Member

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    ringo, it keeps her on her toes!!!!!:D
    chucktx, Nov 1, 2007
    #7
  9. cowboy

    cowboy Moderator Staff Member

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    hee your 81 should not have point's , it was change by the factory about 78 but just incase the small cover next to you right foot two screws hold it on & there in there , put your foot on the floor board & look down :D
    cowboy, Nov 2, 2007
    #8
  10. heebeha

    heebeha New Member

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    No Points

    Ok so what do you guys think is my problem? I ran a direct power wire to the top post and even then the bike lost spark.

    I believe its the ignition coil dont you all?

    Here is a photo of whats inside my timing cover>

    [​IMG]
    [​IMG]
    [​IMG]

    My Coil:
    [​IMG]

    What can I do here to fix my spark? Is it a bad wire maybe or could that igniotion coil be bad, maybe a relay? If so snaybody knwo where it is located. I have a bunch of connectors going to boxes/relays under my tank and behind the headlight as well as a connection box behind the seat.

    [​IMG]
    Last edited: Nov 2, 2007
    heebeha, Nov 2, 2007
    #9
  11. hotroadking

    hotroadking Super Moderator Staff Member

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    Could be ignition
    could be coil

    Those pickups on the back of the nose cone sensors look a little rusted or is it in the picture, it's a magnet system, be sure you are careful putting it back in if you break off a tab you're fubar'd

    And it needs to go back in where it was position wise for timing.

    I would start at the coil, check the wires running back to everything make sure you don't have a short or broken connection.

    Get a multi meter from lowes, ace etc , digital are better and test the connections and wires
    hotroadking, Nov 2, 2007
    #10
  12. heebeha

    heebeha New Member

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    Could the coil be bad How do I test it

    Thats some type of sealant over them. Do you think they need to be exposed? NO rust.

    There are only three wires
    1. To the on off switch white
    2. To I think the pigyback doohiky white
    3. Not sure where it goes but it appears to be a ground when the ignition switch is on blue

    Maybe the coil itsel is not getting a good ground.
    I truly suspect that coil is bad. It seems like when the bike is hot I have te problems. Anyway to test the coil?
    Last edited: Nov 2, 2007
    heebeha, Nov 2, 2007
    #11
  13. Ultra Al

    Ultra Al New Member

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    Electrical problems can be time consuming because as you can tell there are multiple sources for the problem and many have similar symtems. I'd try the suggestions for electronic ignitions already made and I'm going to add one to the list, namely the key switch. If you have a Harley switch you are probable OK but I'd check it anyway. With the motor running just jiggle it and see if anything happens. If it is after market well, the ones I have seen are not as well made as the HD version, the HD switch costs three times as much, natch. AL
    Ultra Al, Nov 2, 2007
    #12
  14. kenfuzed

    kenfuzed Administrator Staff Member

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    If you plan on sticking with the original V-Fire II ignition then your replacement coil is # 31609-80. There is a pretty good aftermarket coil for this one at J&P, just search on part number 381-196. A neighbor of mine recently bought this coil for his 81.
    kenfuzed, Nov 2, 2007
    #13
  15. 2fastnaz

    2fastnaz Moderator

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    Dollars to Doughnuts it's the ignition box. On my 81 XLH it's always the igniontion box.
    2fastnaz, Nov 5, 2007
    #14
  16. hotroadking

    hotroadking Super Moderator Staff Member

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    Before I take that bet are you talking regular Krispy Kremes or chocolate covered???? :D
    hotroadking, Nov 5, 2007
    #15
  17. 2fastnaz

    2fastnaz Moderator

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    Lol
    2fastnaz, Nov 5, 2007
    #16
  18. heebeha

    heebeha New Member

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    Going Electronic

    I am having a Dyna 2000 put on, new voltage regulator, ignition switch, carburator seals were shot - replacing them as well.

    Hopefully she will be in fine shape after the work.

    Fingers crossed.
    heebeha, Nov 6, 2007
    #17

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