Quick question, 77 sporty, when running at idle (1000 rpm), gen light has a dim flicker, when the throttle is opened, the light tends to increase in brightness. I have replaced the brushes, cleaned out the dust in the case around the stator and windings. When I check the voltage, gauge reads 13.5v and the battery is charging. So.....sound like a short? any ideas or thoughts. Thanks

 

If you have the wire diagram for the bike, this gen light always has battery voltage feeding one side of the light and gen voltage coming to the other side of the light via a diode which is not shown in the wire diagram.

When the voltage on the gen side of the light is less than battery voltage the light starts to illuminate, current flow from battery side through the light towards the generator.

When you start the engine and the gen starts turning, there is still a higher voltage coming from the battery than what's coming from the gen.

Speed up the generator and now the voltage from the gen is higher than battery voltage and the current cannot flow the opposite direction through the diode to the light (Unless the diode is shorted). Thus removing the negative potential from the light, turning it off.

Short story long, I'd say have a shorted diode the way yours is acting.

 

Thanks, just got back into town. Will check out the diode and see what results I can get.