wet magneto, no spark

Discussion in 'Electrical' started by Mitch135, May 16, 2012.

  1. Mitch135

    Mitch135 New Member

    A few months ago I left my bike outside and it got rained on. It was just a quick short shower so I didnt think much about it well a few days ago my bike stopped running. After checking everything I found that I had no spark. So I took the screws out of the magneto cover and water ran out. So my question is, is my magneto saveable or should I just buy a new one? Ive already resoldered the blue wire, removed the white wire, and put on a new ground wire and still have no spark.
    Thanks for the help,

  2. Al.Fisherman

    Al.Fisherman Active Member

  3. Mitch135

    Mitch135 New Member

    thanks that's actually what I was looking for, I'm thinking bad coil too just wasn't sure how to test it. I'll go break out my multimeter and see what I get.
    Thanks for the awesome info.
  4. Mitch135

    Mitch135 New Member

    ok so I got everything tested and here are my results:

    Magneto Test:

    ---------------Expected----------My result

    Blk/Wht---------2 ohms------------2.2ohms

    Blu/Wht---------300-400 ohms-----.748 Kohms

    CDI Test:

    ---------------Expected----------My result


    Blk/Blu----------130-150 Kohms-----5.46 Mohms

    Spk/Blu---------135-155 Kohms------5.5 Mohms

    Spk/Blk---------2.5-2.7 Kohms-------2.74 Kohms

    So I'm thinking my coil on my magneto went bad and caused my CDI to go bad? I attached a pic to this post so you guys can see what the moisture did to my magneto. Lets just say lesson learned.
    Thanks for the help and any more suggestions are welcome.

    Attached Files:

  5. Al.Fisherman

    Al.Fisherman Active Member

    Yup.....not good!
  6. 2strokejosh

    2strokejosh Member

    Same thing just hapend to old bike last week.. got stuck rideing in the rain from a mates house (couldn't rain any worse) finally limpd it home running like ****.. Woke up in the morning seen water driping from my magnito bolts.. So I started to undo the bolts when water just started leaking out (steady flow like your fuel tap) drained it all out went for a ride
    1 min up the road it just cut off.. No spark!
    had a spare magnito here chucked it in and BAM she's back to life! Hope you get it going mate.
  7. Mitch135

    Mitch135 New Member

    wish I had a spare but oh well its $12 on ebay. the crazy part is its been at least 3 months since it got rained on so the water slowly did its damage it was running then just gave out after I got back from a ride the other day. Here is a pic of my bike with my new handlebars I just got in today. wish I could ride it...

    Attached Files:

  8. 2strokejosh

    2strokejosh Member

    yep that's the exactly the same problem i'd say.. when I got home from my dreaded rain ride I waited for the rain to stop so I could get it running proply as water alsoo made its way into the carb, Got it running like normal (no splutering) went for a 30 min
    ride all good.. So I took her home (was dark didn't see it dripping) and pulled it out the shed in the morning.. that's when I realized it was leaking from the magnito bolts and all the magnito **** its self!
    Ohh yea nice one mate! Ape hangers!! love the look of them, sus my old bike on my profile Chrome Apeys =)
  9. HeadSmess

    HeadSmess Well-Known Member

    i dont get it. we just had the wettest six months on record, and shelter? my bikes only saw that when i happened to be doing something to them! yet, ive never had water induced ignition troubles...unless you count wet plug boot arcing out onto the frame, that is... only makes starting hard, is fine once it gets hot :)

    so weird.

    and the readings you give for magneto arent too bad. i wouldnt be worried by them. 0.7Kohm is only 700 ohms... not open, not shorted.

    the cdi/coil though...to be in the Mohms means , yes, somethings wrong. probably water gotten in past the potting. hit a reverse voltage across the wrong component and it will promptly die. water being conductive does things like that.

    two tricks? 1. tie the wires so they actully run UP to the hole in the case. so water runs down them, away from the engine. its called a drip loop, and should be visible on every properly installed aerial system. also when a caravans plugged in via extension lead, and just where the main lines enter ones home. water LOVES to run down wires! so far, it doesnt seem to have worked out how to run UP a wire...

    and 2, drill a small hole in the bottome of the magneto case are, or remove the gasket from between the two bottom screws. water gets in, water runs out. :)

    and mount the cdi/coil unit with the ignition lead DOWN
  10. Mitch135

    Mitch135 New Member

    Got my new magneto and CDI today bike is running like brand new again. Thanks for the help everyone.
  11. motorpsycho

    motorpsycho Active Member

    just like the distributor on a car....if it gets wet, you'll lose spark.