1979 Honda Cb750 charging system issue?

1979 Honda Cb750 charging system issue?

Added (1). Had an issue for a while
bike slowly dies on me while driving
the lights slowly get dimmer until there's just not enough electricity to run it and then it dies
tested the stator wires for the correct resistance, they are showing slightly more than the honda maintenance manual suggests but it sounded like the main issue would be if they didn't have any resistance causing an open so i don't think the stator is the issue
hooked up a multimeter to the battery
it held a solid charge for over 5 days

Had an issue for a while
bike slowly dies on me while driving
the lights slowly get dimmer until there's just not enough electricity to run it and then it dies
tested the stator wires for the correct resistance, they are showing slightly more than the honda maintenance manual suggests but it sounded like the main issue would be if they didn't have any resistance causing an open so i don't think the stator is the issue
hooked up a multimeter to the battery
it held a solid charge for over 5 days at 12.3 volts and its only two months old or so, so i think the battery is not the issue
when i start the bike, the voltage drops immediately to 11.8 or so and never goes back up
while its running (i've read that it should be reading 14-15 volts). While running at idle, the voltage drops.01 volts about every 30 seconds. Thats why my bike died on me after about 40 miles of driving it.
i've checked the fuse box and none of the fuses are blown so i'm assuming that the problem is not faulty wiring anywhere on the bike.
I also read and saw some youtube videos where if you get the bike slowly up to about 3000-5000 rpm the voltage should increase… The voltage on my bike jumps around like crazy and is not steady. It also has an average reading of about 10.4 if i increase the rpms right after i start it when the battery is still fresh (compared to the 11.8 volts when just idleing). After releasing the throttle it returns to the 11.8 or so volts and continues to gradually decreas.01 at a time at a steady rate.
i've taken the stator apart, the brushes are good. I also cleaned the surface the brushes run on cause it was pretty dirty. Now i'm stumped. Anyone have any suggestions?
much appreciated, zac