Cursed bike destroyed CDIs

Discussion in 'Motorized Bicycle General Discussion' started by Mr.2Tcycles, Dec 11, 2008.

  1. Mr.2Tcycles

    Mr.2Tcycles New Member

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    OK I think I just bought a cursed bike. I just bought a non functional one, with no spark and replaced the magneto, thinking that was the problem, still no spark. So I thought I would switch out the CDI from the broken bike with one from my other MB that was running great the day before. Still no spark. Switched the CDI back to the running bike and now the bike that was running great yesterday has no spark. Wires connected right blue to blue, black to black, etc. Measured output from magneto of both bikes, and there was output on the multimeter, by that I mean pulses were put out, although voltages were really erratic. What could cause the CDIs to just die? Are they really that sensitive? Also checked if the plug wire and boot were continuous, and they were. I'd really hate to spend 50 something bucks in times like these for 2 new CDIs. Anybody have any ideas?
     
  2. Walter F.

    Walter F. New Member

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    Make sure plug wire is screwed in tight. Walter F.
     
  3. Mr.2Tcycles

    Mr.2Tcycles New Member

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    Both were tight as can be.
     
  4. europorsche914

    europorsche914 New Member

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    i know when i torn my bike down and seperated the cdi from the magneto wires, my bike would not start when the wires were reattached. My problem was the contacts on the clamp on connectors were oxidized. I cleaned them and it worked perfectly!!
     
  5. Mr.2Tcycles

    Mr.2Tcycles New Member

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    Checked for continuity between the connectors (blue and black wire), everything was OK
     
  6. Mr.2Tcycles

    Mr.2Tcycles New Member

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    Is there a way to check the CDI, maybe by connecting it to a 6 volt source then removing it and have the spark grounded on the negative/black side?
     
  7. jasonh

    jasonh New Member

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    that doesn't work, I've tried it. The coil connected to the cdi also puts out like 70 volts or so.

    search for a thread called mag cdi wiring mess. there should be some values to check for with a multimeter.

    http://motorbicycling.com/f34/no-spark-wiring-cdi-mag-kill-2102.html
     
  8. Mr.2Tcycles

    Mr.2Tcycles New Member

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    Here's what it was guys, bad connection between the cap and the wire out of the CDI. Information for the readings of the CDI were a great help in determining if they were cooked or not. The few copper wires in the high voltage wire out of the CDI were all torn, and were intermittent in the connection. Thanks for all your help.
     
  9. TexasDav

    TexasDav New Member

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    Gald you got it running and also posting the solution to the problem.
     
  10. Finfan

    Finfan New Member

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    You should still keep a rubber chicken handy in case the demons return! :eek:

    rotfl
     
  11. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    Walter F nailed it. Always use a good wire, screwed in tight.
     
  12. Mr.2Tcycles

    Mr.2Tcycles New Member

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    OK so I ordered some spark plug wires and boots from SBP, but in the mean time this is what I did, seems to work really well. I have noticed a slight increase in power in both bikes since doing this.
     

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  13. jasonh

    jasonh New Member

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    well that'll work I guess, haha. Keep an eye on that wire, the vibration will probably cause it to loosen or break.

    ....don't go near there when the motor is running unless you want a good shock :)
     
  14. Mr.2Tcycles

    Mr.2Tcycles New Member

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    It's just temporary, I hate having broken things around. As for the shocking done that with these bikes and other engines too. Electrifying experiences.
     
  15. Creative Engineering

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    Oh Me, this reminds of another growing-up experience! You guys remember the wind-up lawn mower starters? Sears...Oh yes I held on to the plug wire and flipped the starter lever.

    Jim
     
  16. Walter F.

    Walter F. New Member

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    How'd that work out for ya? Walter F.
     
  17. Technocyclist

    Technocyclist Motorized Bicycle Senior Technologist

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    That is exactly how they connect the cables to the spark plug in motorboats in the Philippines. :)
     
  18. Mr.2Tcycles

    Mr.2Tcycles New Member

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    Took it out in the rain today, no shocks, and still ran fine.
     
  19. Creative Engineering

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    rotflrotflrotfl It was a real quick lesson on magnetos!

    Jim
     
  20. Mr.2Tcycles

    Mr.2Tcycles New Member

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    Got the new wires and boots from SBP really quick. Bikes seem to run even smoother with a touch more power. Wires and boots seem well made and have a carbon core, I'm very happy with the purchase less than $10 for both wires.
     

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