Lucas/Wassell 1970-74 Norton Commando Main Harness

Grant Tiller

Wassell make a great wiring loom for the Norton Commando.

Specifically I am referring to Lucas Part Number 54960723 which is listed as being for the 1970-74 Commando.

Wassell sell this item under the Lucas name, as they have licensed the rights to use the name for some of the classic motorcycle parts.

An excerpt from the Wassell website about this licensing deal is as follows:

In 2014, Wassell acquired the licence for the Lucas brand from Lucas Industries Limited, for Classic Motorcycle parts. In conjunction with Lucas, an extensive product development programme for Classic Motorcycle parts was initiated, to once again, establish Lucas as a market leader within the industry. Further information is available at

In 2019, Wassell acquired the extended licence for Lucas Classic products, and Girling products worldwide, for Classic motorcycles. The Lucas Classic programme launched in 2019, and included the Lucas Classic Car, Lucas Classic Landrover, and Lucas Classic Motorcycle divisions.

The Wassell history page is an interesting read, and I urge you to take a look!

Grant Tiller

However, since the very beginning, the “Installation Plan” on their website which is also handily printed in colour and included in the packaging when you buy the item is actually wrong.

A special thanks goes to our Norton Commando community friend Constant Trossèl from Holland Norton Works for pointing out the incorrect wire colour on the Master Switch – I missed that one!

Grant Tiller

Here is the original “Installation Plan”

Grant Tiller

I have highlighted the parts that are incorrectly labelled and wrongly drawn – particulalry annoying is that they could not get the Lucas part number correct on their own drawing:

Grant Tiller

This is the corrected version of the “Installation Plan”

Grant Tiller

I have contacted Wassell about this a couple of times in the past, as I have helped a few people that have run in to issues.

However, it has fallen on deaf ears, and several years on they still have not changed it.

Hopefully this will help someone somewhere!!!!

There are several errors on the paper instructions/guides that come with the Lucas/Wassell harnesses.

To my knowledge, the harnesses themselves are fine – they are made by Autosparks, whose history can be traced back to the original ones supplied to Norton.

Here are the pages with corrections:

12 replies

  1. I purchased the exact wiring harness, laid it out on the bench and got out the masking tape and proceeded to tag the terms, yes, I immediately spotted the two mistakes you have shown. Thanks so much for all you do Grant!

  2. Hi Grant,
    Much obliged for your valuable information on this matter.
    I have just purchased this wiring harness for my ’74 and am VERY GRATEFUL for the information.

    Cheers Don from Oz

    • It’s great to hear it helped someone Don!

      Nearly ten years on, despite a number of people telling them, they are still sending out the harnesses with the wrong picture!!!

      Thanks and take care,

  3. Hi Grant,

    I am fitting the Lucas Main Harness to my ’74 Roadster frame.

    Upon testing the earthing system (all red wires back to the red battery eyelet) I came across 4 wires (that were marked as errors in the original diagram that came with the main harness by you). These wires are 3 x red wires and the horn wire. Two of the red wires go into a double connector from the same direction with no wires exiting the other end. These two wires test full deflection on my analogue ohm metre to the red eyelet at the battery end. Then there is the single purple/blue wire that comes from the horn. The 3rd red wire just has a bullet terminal on its end and it does not test full deflection on the metre at all. No movement on needle – does this mean this red wire is open circuit somewhere which I need to chase out or am i missing something else with this wire.

    On your corrected version of the 70-74 Main Harness you show a loop on an earth wire that comes out with the horn wire. So should this red wire with bullet terminal be looped around and back into the double connector?

    Also on your corrected version of the main harness on the bottom side of the main sheathing/wiring there are two large black dots on the end of two earth wires – does this indicate anything of significance (like connect to frame or other place)?

    Thanks again Grant for any advice and help you can offer me.

    Don Clifton

    • Hi Don,

      Yes, there are a bundle of the red cables at the horn.
      The two is the loop in and out for the positive red feed that runs from front to back of the bike.
      The single, if memory serves me right is the positive red feed that goes off to the power socket.
      So when it is unplugged, you should see full continuity both ends (horn end, and power socket end) but no continuity to the rest of the reds on the harness.
      Plugging it in, as I have shown clearly on the amended diagram will liven up the power socket and give you full continuity with every other red cable in the harness.
      This will leave you with one spare port on the connector for the positive feed to the horn.

      The other single cable you should there is a PB (purple and black) cable.
      This should come out at the big bundle of cables under the tank, and is where you plug in the purple and black from the horn push on the handlebar switch.
      You should see full continuity between both ends of the purple and black ends.

      Lucas (Wassell) show ring terminals as the big black dots.
      So the bottom left one is at the head steady, and the other is at the zener diode (they quite rightly do not depend on getting a positive feed from the frame)

      Hope that helps.

  4. Hi Grant,

    Thanks so much for the valuable info. I understand a bit more now.

    More testing to be done with the ohm meter tomorrow.

    Cheers Don

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