Go back to stock regulator, rectifier and battery.
I replaced the Honda regulator since it suddenly stopped charging. Caught in the act after I installed a dig voltmeter. See photo.
Problem understood thanks to forum member bryanj that knew this as an old "known" issue. Regulator relay could enter a middle position. A bump in the road kicked it in correct position and voltage suddenly OK. Exact what I saw.
I replaced regulator with a good old one never tampered with and fine after that.
I recommend a voltage meter. You'll see how the system works and correct values only seen with fully charged battery that take cruising time on +4500 rpms after low rpm riding using blinkers, brake light.
I connected mine to closest black and green. Work fine.
CB750 or 5x0 same #$%* here, right? You'll see the problem before battery is drained.
Dyna 3 ohm coil tested with Dyna-S. Battery drained really quick so back to shop and trade back to 5 ohm version.
These coils now replaced by Honda stock coils from DSS since one of the coils did not work properly on low rpm.
I need to measure both coils before I call Dyna for crap. The Dynatek graphite HT leads I purchased with the initial 3 ohm coils replaced within a year, one of them broken inside from the very beginning.
Occasional issues on one cylinder turned to permanent off. I rejetted carbs in vain!!