This is a custom wiring diagram for Tim Jarboe from the Access Norton Forum – he goes under the name “smokeater”
Electronic Ignition
Tim has fitted a Tri-Spark electronic ignition to his bike.
3 phase Alternator
He’s also fitted a 3 phase Lucas alternator – a great choice for superior charging in modern traffic conditions.
Regulator/Rectifier
He is also in the process of fitting the superb Shindengen SH775 regulator/rectifier – a sensible choice if you are going to fit a lithium-based battery.
Coil
In lieu of the twin 6 volt coils, Tim has gone with the dual output single tower coil from Colorado Norton Works (it’s the brilliant Crane Cams unit)
Wiring Diagram
Here is the Wiring Diagram for Tim’s bike.
Custom Norton MK3 Commando Wiring Diagram – Tim Jarboe PNG 3066×1841
Warning Light Assimilators
It is important to note that MOST aftermarket reg/rec manufacturers do not support either the pre-MK3 Lucas 3AW silver can warning light assimilator OR the MK3 one.
Boyer Bransden are very explicit in their instructions for the Power Bow – they have even made an alternative Power Box model that includes a charge warning light.
Other manufacturers (PODtronics, SPARX and the Tri-Spark MOSFET units) either mention it in their smallprint/FAQs or neglect to mention it at all.
As such, I would recommend NOT using the original assimilator and consider your alternatives.
You could replace your assimilator with a solid state equivalent like the CoolCat Express (warning: you have to buy positive SS3AW-P or negative SS3AW earth)
Alternatively, you could follow my recommendation and buy a Charge Warning Light instead.
A warning light assimilator tells you that the alternator stator is producing an AC output, whereas a Charge Warning Light tells you that the battery is charging, the reg/rec is working and it gives you much more useful information about performance of the charging system and the state of charge.
I personally recommend the Improving Classic Motorcycles “Standard” Charge Warning Light. This model wires in to the standard incandescent lamp, so it looks better than a modern LED. It matches all your other warning lamps, which is particularly important on the MK3 with it’s instrument ‘console’
The ‘brainbox’ is about the size of a postage stamp, and can easily live inside the headlight bucket or under the MK3 ‘console’
Categories: Custom Wiring Diagrams, motorcycles