Off the magneto, one wire splits into two according to this diagram. One splits off to the coil and one goes up to the kill switch and then through the kill switch to the lights...
Since there are not 3 or 4 wires coming out of that magneto, it appears that both your lights and your ignition are on the same circuit.
This seems to means that possibly, a ground or short anywhere on the bike can cause no sspark.
This diagram sucks.. Unless your bike has all these bulbs and components and exactly no extras, find the one for your specific bike if you can