Norton Commando Wiring Diagram + Tri-Spark + cNw + Podtronics

Grant Tiller

As promised, below you will find the wiring diagrams which have been modified to include Tri-Spark electronic ignition, the Podtronics regulator/rectifier and the Colorado Norton Works Electric Start Conversion.

Pre-1971 (ammeter in the headlight shell and Wipac Tricon type handlebar switch) PNG 3066×1841

Grant Tiller

1971 (three wires to the master switch) PNG 3066×1841

Grant Tiller

1972 onwards (four wires to the master switch) PNG 3066×1841

Grant Tiller

Very popular modifications giving you a bike that is suitable for modern day motorcycling!


A couple of points about the way these diagrams have been drawn:

  1. Where the same colour wire goes in to and out of a single connector, that connector has usually been omitted from the drawing.
    It’s obvious on the bike, is easy to spot and easy to troubleshoot.
    Leaving them off the diagrams makes them a LOT easier to read, and considerably less cluttered.
  2. Wherever the earth or ground side of a component goes back to the battery, the drawing shows a red earth symbol:
    Grant Tiller
    In reality, this could be connected either to a red wire in the bike’s wiring harness (loom) OR it could be attached to the frame or engine of the bike.

    I have shown the red earth symbol each time in order to massively simplify the diagram, and make it a lot easier to understand for everyone.

    I have also coloured them red as a gentle reminder that these bikes are wired positive earth!

5 replies

  1. Grant, what program are you using to do these? I’m specifically interested in the ability to get the two colors on the wires. Thanks, David

  2. Hi Grant,

    Further to my recent last email – apologies. I found the wiring diagrams after I sent the email!

    Just a quick question.

    Do I need to fit a ‘noise filter (?)’ to the system to prevent misfiring problems with the Trispark system or just use a different rec/reg to the Podtronics.


    • Hi Dave – great to see you have found the cNw wiring diagrams.

      If you have anything different to what I have listed here, don’t hesitate to reach out.

      If your Podtronics and Tri-Spark combo are fitted and are not showing any issues, then you are good to leave everything exactly as it is.

      The issue does not seem to manifest on all Podtronics units, just a few of them.

  3. Thanks Grant, your reply is appreciated.

    I haven’t purchased any components yet and might just get the new stator and MOSFET kit from TriSpark when I get the new ignition system. I imagine I would then just substitute out the Podtronics reg/rec in the diagram.


    • David,

      I really like the Shindengen open-type reg/rec.

      I use them myself, recommend them to others, and have never seen one go bad.

      There are a lot of counterfeit units on the market, so be careful.
      Maybe order one from Jack at Roadster Cycle (, and get him to ship it to Matt Rambow at Colorado Norton Works, to include in the box to you in Australia.

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