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  1. #1
    CB750 Member Usarmyguy91's Avatar
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    Both coil wires constantly have 12V

    Hello, Iím new to the forum. I just installed a new wiring harness on my 78cb750 and a an electronic ignition. And when I hook the test light up to the blue or yellow wire coming from the coil the light stays illuminated. The wiring for the coils seems so simple where could I of messed up???

  2. #2
    Moderator dirtdigger's Avatar
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    So it stays on constant when you are cranking the engine over?

  3. #3
    CB750 Member Usarmyguy91's Avatar
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    Quote Originally Posted by dirtdigger View Post
    So it stays on constant when you are cranking the engine over?

    When I turn the key on itís sending 12v to both blue and yellow wires. Havenít even tried turning the bike over. Keep in mind I just installed a whole new harness so I may of hooked something up wrong

  4. #4
    Moderator dirtdigger's Avatar
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    When its not running you will always have power running through the coil, you dont get ignition pulse until you crank it and the ignition pickups turn the coils on and off. When you just have the key on you send power to the + side but if its not running you will see it on the - side as it is a complete circuit if the engine is not being turned over. Take the blue and yellow wires off the coils and you should not have power on those wires but you should have power on the wires still connected to the coils.

  5. #5
    CB750 Member Usarmyguy91's Avatar
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    But to time the electronic ignition it says to put test light at the junction where the blue and yellow wire connect to the coil and when the timing hits right before top dead center the light should turn on signaling that coil to fire the coresponding cylinders. Iím sorry but you have lost me.

  6. #6
    Moderator dirtdigger's Avatar
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    Have you tried cranking it with the test light on the blue or yellow wire? If it flashes when it is cranking you probably have the wiring correct if it never flashes on either of the colors then you have a wiring issue or a ignition issue. Crank it over see if it works, no point messing with trying to time it if it is wired incorrect and you are getting no flash at the coil.

  7. #7
    CB750 Member Usarmyguy91's Avatar
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    I have noticed that the light flashes brighter when Iím cranking it. But canít time it that way. Still donít think it right. Hopefully someone can provide some insight. I wouldnít be surprised if I have something wired wrong or not grounded correctly.

  8. #8
    Moderator dirtdigger's Avatar
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    Without details on ignition, pictures or diagrams of how you wired it I guess I cant help. You will see a definite flash of the test light when cranking it over if the ignition is wired correct.

  9. #9
    CB750 Member Usarmyguy91's Avatar
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    Still needing help with my ignition problem.

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