Ignition Issue (possibly CDI wiring)

  • Hi all,

    Rebuilt my bike (3RN I believe). I came to kicking it over and it wouldn't start. Removed spark plug and tested for a spark. It didn't. However, after testing for a spark i turned the kill switch from 'on' to 'off' and as it toggled the spark plug zapped me. Therefore, somewhere my wiring must be wrong. Did this twice and confirmed it only powers the spark plug when toggling the kill switch after kicking over. The bike is purely kick start. See below.

    The bike is no longer road worthy and it was converted to an off road bike by the previous owner. Therefore; speedo, ignition, lights, battery, stand etc etc are removed. As a result, most of the cables on the CDI unit have been previously cut and taped up.

    The only cables used on the CDI:
    Orange (to HT coil)
    Black (earth)
    Green and white (stator)
    Black and red (stator)
    White and red (stator)
    Black and white (kill switch)
    Light blue (currently going to earth)

    The following cables are not used:
    Black and yellow (no idea)
    Blue and yellow (cut - should be side stand i think)
    Blue (cut - should be neutral lamp i think)

    My questions are:

    What does the sky blue cable do? Should it be going to ground (considering the systems that aren't on the bike now)?

    One cable going from the stator to the CDI begins life as a white and blue cable. It then goes to a joint and turns to a black cable. Should this black cable join to the other black earth cables? The wiring diagram in the Haynes manual (page 173) shows the colour change is correct, and also shows 2 black cables for the CDI but my CDI only has 1. I currently assume all black cables are to earth and have wired it as such. Is this correct?

    What is the purpose of the black and yellow cable? I cannot tell from the wiring diagram in the Haynes manual. I remade the wiring loom myself (by copying the previous cable) because it was in a bad state, and have (probably incorrectly) connected the black and white cable from the kill switch to the black and yellow cable on the CDI (from memory the previous owner had done this). Now I have checked The Haynes manual it shows black and white should go to black and white on the CDI so I plan on making this change. Without knowing what the black and yellow cable does I am not 100% that this is the problem. (Although it is the most likely issue).

    Any help or comments will be very much appreciated. Attempted to attach the haynes diagram and a picture of the CDI but my phone won't allow it.

    Many thanks in advance everyone! Appreciate its long winded but feel it needed to be!


  • Had this issue years ago on a 2001 DTR. Literally the bike would not fire with the ignition in the "On" position. But would fire in Off.

    Ended up having to simultaneously kick the bike over, whilst switching the ignition from Off to On, in order to get running lights etc.

    The issue in this case was the Side Stand switch not being deleted properly and causing problems.

    With yours, because so much is changed, it's an electrical gremlin that can be annoying to chase.

  • @Calum yes certainly is a pain to work out whats wrong! Knew others would have had similar issues! Cheers mate.

  • Hi mate sounds like a bit of a nightmare you got there. I would try unearthing that sky blue wire as I think it's for the neutral cut out switch and I may be wrong, somebody please correct me if you know different, but I think by earthing it the CDI thinks it in gear so won't start.

  • @markus-w thanks mate, i'll certainly give that a try! Cheers.

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