Finnius

Hey folks, I am doing up a 1979 AG 100, which at the moment is in pieces. The frame will be stripped back, painted then the rest of the bike built back again. I was wondering if anyone could tell me what the wires that come out of the engine are for. There are five or six wires that are color coded, i imagine one is for the 'neutral' light, one is power from the magneto etc? I was hoping i could isolate the wires that are critical to the engine running for troubleshooting purposes, as the wiring harness is in poor condition and i will probably be rewiring the bike myself. Thanks for any assistance or tips. I might be asking more questions once i try and get the engine running!