Update - running like new...

grandpaul said:

Same goes for Tri-Spark. With the significantly higher price of Tri-Spark units, it just took them longer to get to "critical mass"...

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Maybe, but we have one member here who had issues with multiple tri-spark units on his bike so he switched to something else. I bought his 2 tri-spark ignitions and one of them has been on my bike for a year now working flawlessly. The TS gets its ground through the engine cases, and the grounds on my bike are bullet proof. My point was that there may be TS failures that are simply due to bad engine ground.

The percentage of early life failures is about the same across Tri-Spark, Boyer, Pazon, Sparx and Wassell (Vape)
The Sparx alternators and reg/recs are a whole different story!

Take Boyer Bransden as an example:
Most of the Boyers fail when the soldered wire joint at the stator is not strain relieved and shakes off.
Other issues occur when the voltage drops under twelve, which the MK3 Boyer doesn’t like - not a fault of the ignition unit.
Both issues were resolved on the MKIV unit.

People still relate the Tri-Spark failures to a failed Honeywell component in the original version of the Classic Twin - this was resolved years ago.
Other perceived failures that I have run into usually boil down to wiring issues.
Do bear in mind that the Tri-Spark is the only unit that gets it’s positive feed from the lower crankcase - the other popular all in one unit is the Power Arc which comes with a long set of wires that all head up to the where the coils are.
This is the my reasoning for recommending running a positive up to the coils, for the reasons I have already highlighted.



With the exception of the turn signals, every component on the Commando has its own positive feed from a wire that’s part of the harness - there is no reliance on passing a current through the frame or the engine.
So why introduce that reliance and potential point of failure if you don’t have to.



In my experience, the majority of electronic ignitions that are declared broken have nothing wrong with them.
You can verify this with any manufacturer - they’ll tell you that most of the units that get sent back for testing actually check out fine.

gtiller said:

This is the my reasoning for recommending running a positive up to the coils, for the reasons I have already highlighted.

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My bike is negative earth, so no ground at the coils. It's the black wire on the TS that needs to be grounded in this case. One thing to add here is that when setting the timing the points plate studs need to be loose enough to move the ignition relative to the rotor, and I always run a temporary ground jumper from the TS to the harness (or engine) to be sure there's no loss of connection while adjusting timing.

@maylar i’m referring to standard bikes.

And yes, for a negative earth bike, it is the Tri-Spark black/yellow that is grounded.
Even then, I’d suggest running it up to the ring terminal at the headsteady rather than relying on getting a good continuity back to the negative side of the battery.

Of course my recommendation doesn’t apply to you because you have ‘bullet proof‘ grounds.
I’m only trying to help everyone else.