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Boyerbrandsen No Spark

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  • Boyerbrandsen No Spark

    Vintage Technical Tips & Tricks
    Boyer Igniton No Spark
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    Joined Oct 31, 2018 2 Posts
    Discussion Starter #1 6 h ago
    1971 T 120 R
    MK 3 Boyerbrandsen installed 10 years ago, no problems. Earlier this summer, started smoking, barely running on one cylinder. Owned since new, many miles, did a complete top end job. First kick, ran for about two seconds on one cylinder, many kicks, nothing. Wait 30 seconds, try again, same thing ran for a second or two did this till I gave up. After looking at fuel I took out a plug, grounded it, no spark.
    New AGM battery, strong headlight, measures over 12 volts with the headlight on
    New plugs, solid copper high tension wires and checked them for continuity and high resistance.
    Followed all the trouble shooting tips.
    Sparked the stator wires
    magnets 66 ohms each, 132 ohms across the two.
    Magnets on both coils support the stator hanging from a wrench.
    Cleaned all the grounds. Checked all the wiring, fuses & circuit breaker even though I had not disconnected anything.
    Checked the 6 volt ignition coils that were installed with the boyer when I installed it.
    Resistance of the primary and secondary are within specs.
    Bypassed everything. Direct from battery to Neg on the box and from Battery to Positive.
    The only thing I thought was left was the black box.
    Installed a new MK 4. Same problem! No spark either cylinder.
    Disconnected the wiring to the coils and hot wired each one, both produced a spark when I sparked the Neg. post
    I don't know what else could be the problem except a faulty brand new MK IV black box.
    Anyone get a bad MK IV right out of the box?