This is a sister article to my Norton Commando Wiring Diagrams page where I have colorised and corrected the factory workshop manual wiring schematics for the Norton Commando. You can find by clicking here.

In this article, I have broken each wiring diagram into separate circuits, covering ignition, charging, lighting etc…

This will hopefully make it much easier for those who are not familiar or comfortable with automotive electrics to visualise and understand what’s going on inside the wiring loom!

By seeing the circuits split out into their specific jobs, it make it much easier to troubleshoot and repair issues.

Below is a clickable table of contents, that will take you to the right section on the page, to save you from scrolling.

	Ignition Circuit
	Charging Circuit
	Lighting Circuit
	Turn Signal Circuit
	Brake Light Circuit
	Electric Start Circuit

Ignition Circuit

It’s worth noting that the earliest Commando points ignitions were based around 12 volt coils.

When electronic ignition systems (namely the Lucas RITA and Boyer Bransden) first started surfacing, they called for 6 volt coils (as they were to be wired in series as a pair)

This was overlooked by many, as was the reasons why many of these systems burnt out, and were consigned to a box under the bench or returned to the manufacturer for replacement.

1968 Norton Commando
1971 Norton Commando
1972 onwards Norton Commando
1974 Norton Early MK3 Commando
1975 Norton MK3 Commando
1975 Norton MK3 Commando (Canadian Market)

Charging Circuit

The rectifier was always Silicon on the Commando – never Selenium as some “noted experts” say. It consisted of four diodes sandwiched between cooling fins – the soldered joints are susceptible to vibration.

The half-wave rectifier used on the MK3 is half the normal one used on the pre-MK3 – with just two diodes. Full-wave rectification is achieved by the two zener diodes which are performing two roles – regulation (limiting voltage) and rectification (converting AC to DC)

The blue can smoothing capacitor is only good for around 10 years before the electrolytics start degrading.

The Warning Light Assimilator is not compatible with most modern aftermarket regulator/rectifiers, so must be removed.

1968 Norton Commando
1971 Norton Commando
1972 onwards Norton Commando
1974 Norton Early MK3 Commando
1975 Norton MK3 Commando
1975 Norton MK3 Commando (Canadian Market)

Lighting Circuit

Note the MK3 Canadian Market bike where it was legislation for the headlamp to be illuminated when the engine was running.

The Warning Light Assimilator was swapped out for a Headlamp Warning Unit, and coupled up with a special version of the Ignition Key Switch.

1968 Norton Commando
1971 Norton Commando
1972 onwards Norton Commando
1974 Norton Early MK3 Commando
1975 Norton MK3 Commando
1975 Norton MK3 Commando (Canadian Market)

Turn Signal Circuit

Obviously no turn signals for the 1968 bike, so no diagram for that.

Turn Signals became standard on the 1972 Combat spec bikes, however the wiring was included from the 1970 Interim (1971 model year)

One thing to note – Norton put out a Service Bulletin in May 1972 with details about switching Left and Right side handlebar switches. More info can be found here.

1971 Norton Commando
1972 onwards Norton Commando
1974 Norton Early MK3 Commando
1975 Norton MK3 Commando
1975 Norton MK3 Commando (Canadian Market)

Brake Light Circuit

There is no brake light switch shown on the original 1968 factory workshop manual.

This was included only for the US market originally, however is standard on the replacement harnesses available.

Note the ‘hot’ White for the front switch which came off the ignition coils as per the US predecessor to the Commando, the P11A (aka the Ranger)

1968 Norton Commando
1971 Norton Commando
1972 onwards Norton Commando
1974 Norton Early MK3 Commando
1975 Norton MK3 Commando
1975 Norton MK3 Commando (Canadian Market)

Electric Start Circuit

Obviously only the MK3 is covered here.

The starter motor was ‘down-specced’ originally to two brush and two field coils and coupled with lighter than ideal cables to power it.

This was not done at the time to reduce costs as reported by some “noted experts”, but because Lucas and Norton were both painfully aware that the battery capacity and charging system (due to technology limitations at the time) were not sufficient enough.

1974 Norton Early MK3 Commando
1975 Norton MK3 Commando
1975 Norton MK3 Commando (Canadian Market)