This bike came with no key. It is "on", and will start when you kick start it. It has a kill button that grounds out the "magneto".
I don't have a charging system. What I've built is a standalone/isolated battery operated lighting system. It is grounded to the frame/engine, but I have no regulator/rectifier.
I did install an ignition switch. In the off position, it closes the kill switch circuit. All I had to do there was patch into the exiting kill button wiring. So I can kill it with the button or the ignition switch. I mounted the switch left of carb under the seat. It is close to the kill switch wiring, and on the way between the battery and headset. Made sense:
In the on position, the kill circuit is opened, and 12V goes to the tail light, turn signals, DRL in the headlight ass'y, horn, tail lights, brake light switch (front lever-hydraulic compression switch), the headlight relay, and the headlight switch gets power. When I switch on the headlight switch, the headlight relay is triggered and the headlight turns on, selectable hi/lo beam on the handlebar switch cluster. This way, I get center tail light and DRL draining the battery unless I use the turn signals and when I hit the brake. Activating the headlight relay with the handlebar switch also turns on the running lights (led) in the turn signals. Brake switch lights up the center AND the two turn signal brake lights, even without the headlights turned on. These little button led turn signal lights have running lights (red), brake lights (red), and turn signals (amber), and a ground wire, so there are four wires coming from each one.
If you have a basically intact wiring harness that you can clone, that would definitely be the best way to go about designing a new harness. As you remove it, you can even label each terminal so you know what it connects to while you are building it on the benchtop. My design won't really work.
I might eventually add a reg/rec, but it may need a higher output stator and the ignition module may not be compatible. I don't know how it is wired in a standard harness with a charging system. My battery tray is identical with the models that HAVE a charging system, so I have mounting positions for a reg/rec and whatnot. I am hoping that my isolated battery powered led lighting system is durable enough to keep me legal and safe when I have to be on a (forest) road
I will make a wiring diagram though I don't know the proper way to indicate standard features. It will be interpretable and anyone that wants to add an isolated lighting system will be able to use part, or all of it for their conversion.