Saturday, 7 October 2023

Dre-XT-Stück - no ignition advance & ignition pickup waveform analysis

If you're just interested in the solution, look at the picture below, spot the brown cable and smirk, because there's a red cable plugged in. 

With that out of the way should you ever be in the position to question whether your stator was wound incorrectly, here's a few things to know beforehand:

  • common ground for the pickups is green
  • 12 degree pickup connects to white-green
  • 36 degree pickup connects to white-red

If you hook up an osilloscope and have the polarities of the AC-supply mixed up like I did, this is the waveform you'll see at idle (and also higher revs, because the ignition will not advance), i.e. around 11V peak to peak:



 Once hooked up correctly, the peak-to-peak voltage will be under 9V and with a much more civilised wave form


And here in the form of a video to show how I set up my equipment and how the waveforms change depending on RPM, i.e. if you're troubleshooting, what to expect.


For more information on the background on how the actual ignition works check out transmic's website, which has some lovely graphs and pictures of the CDI: Transmic

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