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There is no 12 volt *ANYTHING* in your ignition system. The spark come from the CDI. The CDI is powered off a high voltage AC winding on your stator. The CDI is triggered by another lower voltage AC winding on the stator. Then somebody tells you you should have 12 volts at the coil, and then you measure 12 volts. This has me a little worried.

Below is what the voltage should be on your igntion coil. There are actually two different waveforms because I have two different brand CDI's. Both work fine. CDI's should be considered black boxes that take in the stator high voltage AC, the trigger pulse. the kill switch connection, and then produce an energy pulse that will couple through the ignition coil to fire the plug. There are many, many ways to do this. I think these two examples show how bizzare the differences in designs can be. So what what would your meter show for these waveforms? I have no idea. It depends on how the meter is designed inside. Different meters will read differently.

The following was measured with an oscilloscope at engine idle. At cranking speeds the waveforms would be the same except the amplitude would be smaller, and the time between pulses would be longer. An oscilloscope is just a fancy voltmeter that is able to measure very fast moving voltages and plot them graphically over time. The horizontal axis is time, the vertical axis is voltage: Use the horizontal scroll bar to see the detail on the right of the graph.

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