Motorcycle Repair: Source lighting coil, volt system, source lighting

Question
I have a 1974 175DT Yamaha enduro. It is a 6 volt system. Although I replaced my battery and head light bulb, the head light does not work. Is it necessary to have the engine running to have juice to the head light? Is that what the lighting / source coil does?

Answer
Steven, not being a Yamaha expert, we have to dig into microfiche for some clues...

http://www.cmsnl.com/yamaha-dt175a-19741975_model8509/partslist/B-11.html  #3

So, yes the engine has to be running to supply voltage to the headlight. That is what the lighting coil does.

Bill Silver