Electrical issues after rebuild. Magneto?

Discussion in 'Electrical' started by StrangeTechnician9, Sep 6, 2012.

  1. StrangeTechnician9

    StrangeTechnician9 New Member

    So I rebuilt the engine to replace leaking crankcase seals. I now have wonderful compression. I'm kind of excited about that other than the fact that its a little harder to turn over to test a spark.

    I attached an automotive test light to the fins of the engine (and spark plug once to be sure) and jammed the sharp end into the end of the cdi wire. (no spark)

    I then attached the test light from the blue wire out of the engine to the black wire out of the engine... no light

    I measured the resistance between the blue and black wires. 351 ohms

    Starting to figure out what this "air gap" is in another thread.

    I hate dealing with Piston Bikes and I've spent a lot of money recently on this stuff. I'd really like to fix this problem instead of replacing things again if possible.

    Thanks for all your help so far. This site is amazing.

  2. Purple Haze

    Purple Haze Active Member

    Your ohm reading should mean the coil is good. Look at the ground, these things are touchy about being grounded. Clean all contacts well. Also, check the magnet for proper orientation on the shaft, if it is backwards the timing will be way off. At top dead center on the piston, the keyway should be at 1 oclock. Good luck and hope it is a simple fix.
  3. crassius

    crassius Well-Known Member

    could be something strange like the white wire having a bad spot in the insulation that allows it to short to ground, or maybe the kill switch is stuck in the 'kill' position

    as a last resort, I often take the plug out, hold it in my hand with my hand grounded to the engine and crank the engine real fast - if it bites, your plug is shorted internally
  4. StrangeTechnician9

    StrangeTechnician9 New Member

    When I took the engine apart I couldn't figure out how to get the magnet off so I hope it is still in correctly. I did however take the magneto out. Could I have put that in backwards? Would it make any difference.

    I'll cut the white wire off where it starts and see if that does anything. I don't think its the plug though..

    By grounded do you mean the black wire being attached well?
  5. crassius

    crassius Well-Known Member

    at TDC, the keyway of the rotor is at about 1 o'clock

    the blue wire is at the top of the stator coil
  6. BigBlue

    BigBlue Active Member

  7. TomONaBike

    TomONaBike New Member

    the cdi wire doesnt always connect, some times the copper wires get buried into the sides and you need to cut the end off to get a fresher connection. and for the spark test, i dont know how that works with the auto test light, but i connect the cdi wire to the boot and then the spark plug and set the plug against an acorn nut.
  8. StrangeTechnician9

    StrangeTechnician9 New Member

    Cut white wire off from where it begins

    Checked to make sure coil was in right

    Checked magnet keyway 1 o'clock at what seems to be tdc.

    Changed plug.

    Made better connections to the CDI.

    Thank you everyone, I now have spark. :) It even starts up and runs kinda. It doesn't run well but I think I can move on to my fuel problem now.

    Thanks again.
  9. crassius

    crassius Well-Known Member

    if you've been spinning it a while without it starting, you may have a lot of gas & oil down in the bottom - it will run bad & smoke a LOT

    just run it slowly for a while till the smoke becomes normal again and it should start running better

    (I REALLY wish these things had a drain plug)