Minimum wiring to check spark!!

I pulled the wires off the main harness. I now basically have only three wires, the rest aren't hooked up any longer.. They come out of the magneto, and they are black (or brown), red, and blue. How can I test the spark with just these 3 wires?? I know someone said hook up only the condensor and the points. I don't want to mess anything up though. I thought if I just take the red wire to the coil, and then ground the black wire, I can test for spark, but I am not sure if I'm right. Any tips on how to do this would be really appreciated. I've checked other posts and I just don't quite understand what they mean by just hook the condensor to the points. I don't know what a point looks like, and my wire coming off the condensor is white (or grey).

Re: Minimum wiring to check spark!!

I included a hand drawn diagram of what I'm talking about. I hope it's fairly easy to understand. Any help will be appreciated.

1116365361_moped_wires.jpg

Re: Minimum wiring to check spark!!

Don Pflueger /

the first thing you need to know is which two wires are power supply, and which wire is the ground thru the points. use your ohm meter with one meter lead on each wire, and the other lead to ground. roll the engine over and you will see OL when the points open, then an infinite reading when the points close on only one of the wires.

once you know which wire is the ground thru the points, then you can use one of the two other wires to try to get spark. so put one of the two wires on the + terminal on the coil, and the negative wire on the - terminal on the coil. if your points are gapped correctly and working properly, you will see spark.

Re: Minimum wiring to check spark!!

Take a look at this pic. It's a very basic points/condenser ignition diagram. If the wire connection between the coil's - negative pole . the condenser and the points was "grounded" the ignition would not be able to spark. This is what a kill switch (and ignition-off switch) does. The points are inside the flywheel and look similar to the picture.

Imagine replacing the battery with the spinning magnets and coils of wire of the magneto. A magneto generates power for ignition without a battery.

If something in the frame's wiring harness or switches is broken, the magneto might be able to cause spark but whatever is broken is preventing it.

To test for spark without all the switches and stuff, minimize things so that only the essential parts are connected.

Be aware that if you do it and the bike starts, you have no electrical way to shut the engine off. You could use a pair of insulated pliers and pull the spark plug boot off.. or cover the carburetor's air intake.

Re: Minimum wiring to check spark!!

Don Pflueger /

the first thing you need to know is which two wires are power supply, and which wire is the ground thru the points. use your ohm meter with one meter lead on each wire, and the other lead to ground. roll the engine over and you will see OL when the points open, then an infinite reading when the points close on only one of the wires.

once you know which wire is the ground thru the points, then you can use one of the two other wires to try to get spark. so put one of the two wires on the + terminal on the coil, and the negative wire on the - terminal on the coil. if your points are gapped correctly and working properly, you will see spark.

Re: Minimum wiring to check spark!!

Don Pflueger /

hmmmmmmmm. not sure why this posted twice. weird

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account