Thank you all for such great information on the site! I'm much appreciative. Ive tried to search for the answer but Im having trouble finding out how to test the coils for the charging system. The bike runs so the mag works (black wire is hot) but no power for the headlight or charging (green, yellow, light green and green and white no power)? Would this be the lighting coil? There are three coils are they all connected together?

Clarification, found 1.4v at battery connection no.1 position, no 2 position I got 2.8v (unplugged from battery) so its charging. Checking each wire coming out of mag Nothing from yellow all others are hot, bout 1.2v at idle. I cant get the headlight or instrument lights to come on? I checked the bulbs, they are good. The blue, green and yellow in the headlight can are dead, no voltage.

What are you using to check the output?

Hey Mark,
I’m using a volt meter.
Thanks

Set on AC volts with one lead to a good ground?

Ha! That helped, wasn’t set on ac... seems good.
I think the rectifier would be the next stop?

You already said battery was charging. Rectifier turns AC from green to DC to charge battery.

Headlight runs off AC from yellow.

You are correct, just trying to figure out the next thing to check. Rectifier seems good too! Here is one I’m struggling with, I checked continuity between the yellow plug near the battery to the yellow plug at the headlight with success. But when I start the bike and check for ac at the the same headlight plug I have none!

I replaced the main switch on this bike with one from a 1973 ct3, looking at the wiring diagrams I couldn’t find any difference. I may be mistaken...

If your bike is a 73 model , it is a CT3 . You can check VIN numbers in the Tech Section to verify .