Fried my magneto coil...

Discussion in 'Lighting and Electrical' started by Teratoma, Jun 13, 2014.

  1. Teratoma

    Teratoma New Member

    Apr 24, 2014
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    Hi everyone.

    I built my first gas bike and joined the site about 3 months ago - minimal problems so far, and people here have been very helpful.

    Not really looking for help this time since I solved the problem myself and was able to cannibalize a working coil off one of my roommate's spare motors. Just wanted to say hi and relate my observations.

    The old (working) coil I put in was grimy and oily, while there was nothing visibly wrong with mine (which was officially declared dead by a voltage meter) all the connections were solid. The first time I started her with the new (old) one, she started with such power and IMMEDIATELY started to hum. I cranked the throttle and she squealed!

    What is notable about this was that prior to this, she took a bit more effort to start, and would perform sluggishly for the first block or so. I could rev the throttle to warm her up quicker, but if I did it too hard too soon she'd die.

    And now she's performing better than ever, right off the driveway!

    I guess it does make me curious though, does a condition like that cause performance/efficiency issues the whole time the bike is running, or just when it's 'warming up'? Was I wasting fuel before? It's a very noticeable difference in how it runs now; should I notice my tank taking me further?

    I guess I'll find out over the next week but I'd love to hear any input!

  2. maniac57

    maniac57 Old, Fat, and still faster than you

    Oct 8, 2011
    Likes Received:
    Sounds like classic weaker spark symptoms.
    The new coil cleaned up your combustion and reduced four-stroking due to the spark being blown out or overpowered.
    Might check the jetting. A stronger spark can change what the motor likes.

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