Hi Folks,
            Firstly thanks for allowing me access , much appreciated. I am in the process of constructing a minimal wiring loom for a Savage engine ,sorry , I don't know the year, it's mounted in a vintage Ariel frame .I could do with knowing what the black wire on the ignitor does , it looks like it goes to the starter solenoid and is energized when the starter button is pressed. It appears to put out around 5 volts output when the box is powered up. I don't have sparks at the moment but I don't want to connect this wire up until I know what it does. Pick up coil has around 500 ohms resistance and I can get the plug to spark by switching power to the box off so I know the high tension side is good. Thanks in advance , David.

Thanks for the rapid reply, the link to engine numbers is a great help, unfortunately the wiring diagram links don't appear to work however I do have a Clymer manual so that's not really an issue. What I really need to know is the function the black wire performs as opposed to where it goes. Once again my sincere thanks for your time. David.

Thanks , black/white is earth on Suzukis , from memory the black/yellow feeds the pick up , it's the plain black going to the starter solenoid that has me confused. but as I say thanks for your input. David.

Just speculating here, but remember how old time points ignitions would bypass the ballast resistor when cranking, so the coils could produce a nice hot spark even though the starter motor was dragging system voltage down a few volts?

Now, we have ICUs that will entirely refuse to make sparks when system voltage drops below the programmed threshold.  (Usually around 10V DC)

My guess is that DC voltage coming from the starter solenoid, on the Black wire, tells the ICU that the Starter Motor is active, and thus to ignore it's internally programmed cut-off threshold, and make sparks while cranking, even with a lower system voltage.