Woo Hoo! Got the old beast running better than it has in the 2 years I've owned it! It had been running badly and intermittently on one cylinder. I made new spark plug wires. Helped, but not a fix. Started cleaning electrical connections and checking grounds... Bingo! :+1 The bike IS 25 years old after all! Took it for a spin this afternoon. Wow! Now this is how these old mills are supposed to run!! ;-T After it was nice and hot I had to turn down the idle screws. The idle had gone from 700 to 1500 rpm.
Dang. I was worried I'd be out $200 for another Dyna box. Looks like it was just a poor ground.
Really happy with it now.
That's great, and another example of the old saying (well, I don't how how old it is but I live by it) that "95% of all motorcycle electrical problems are caused by a bad ground or a bad battery."
We always want the problem to be something we can unbolt and replace, like a coil or a box or a connector, but it's generally bad grounds, as you found.
Happy trails!
Lannis