Electric issue

[bheezy27403]

My '74 350 has been having intermittent issues. Sometimes she won't start, dies at stop lights while idling, etc. Turn on key, bright neutral light. Turn on engine switch, light dims considerably. If it fires, while idling, if I hit the headlight it will kill it. Not every time but I can tell when it will from the brightness of the neutral light. It wouldn't start yesterday, today fired on first kick. Made it most of the way to work then died as I was coasting to a light. Once I got it off the road I turned the key and the N light was dim, when I turned on the engine switch barely visible. Never re-fired.

The batt was in spec (the shop said last time I was there). I bought a new one but haven't installed yet. I have to change the leads out to fit the new batt but it seems more of a charging issue.

Thoughts?

[Striker1423]

Start with checking charging output at the battery (once you replace it). Should be around 10-11 volts at idle and around 13-14 volts at roughly 3k rpm. These bikes don't really charge at idle when stock. So, typically they will drop a cylinder when the voltage goes below around 10volts on an old battery. What causes that? Either a dying battery, bad grounds, stop and go traffic, or a voltage regulator/rectifier that needs adjustment. Yes, the stock ones are mechanically adjustable. They don't typically require it and I don't fully remember the adjustment instructions, but someone here might. If your output is like 17-20volts, then your voltage regulator is either dead, or in dire need of adjustment. Stuff starts cooking at those higher voltages. Although, I doubt it. Those higher volts start blowing bulbs and that's not what you're experiencing.

Double-checking grounds is never a bad idea. Also the negative battery cable and subsequent connections.

If the output is in spec (again 13-14 v at 3k), then the hunt begins to find where your short-to-ground is, etc. 

[m in sc]

yup. charging issue 100%