Hi,
Just joined the forum and have a similar problem to you.
Did you find a solution?
I too have 3 wires (other than to the coil); yellow - which is
for the headlight; green which is for the stop light and
red(but sometimes its white) for the tail light (details taken from a Motoplat site).
I too want to run without a battery.
Can you (or anyone else) help with a diagram and a list
of the parts needed.
Thanks