I know this is an old thread but I would like to revive it as I seem to have EXACTLY the same problem as the original poster on a 1975 CB200T. To the OP: did you ever manage to solve your problem ?
Battery test
Measured across the battery, I'm getting about 12 v DC at idle, but only it goes up to 12.6 v DC at high revs, not enough to charge the battery. It drains slowly though, and I can use the bike every day for a week or two before I have to recharge the battery.
Stator test
I measured resistance between the three leads coming out of the stator and get 0.6, 1.8 and 2.1 ohms, which is exactly what the OP got on two different stators. I've seen many videos on youtube saying that anything above 1 ohm is a sign of a bad stator, but here we have 3 stators producing the same readings. Are they all bad?
There is no continuity between the stator leads and ground.
AC voltage readings between the three leads (A-B, B-C, C-A)with the stator plug disconnected (all three leads are black):
idle / 3000rpm / 5000 rpm
16 / 40 / 65
10 / 25 / 42
6 / 16 / 22
Is this enough AC voltage to charge the battery?
Rectifier test
(Pink and yellow wires come from the stator. Red/white goes to the battery. Green is ground.)
From yellow to red/white (+) = 0.6 ohms
From pink to red/white (+) = 0.6 ohms
From green (-) to red/white (+) = 1.3 ohms
No reading in the opposite direction.
Regulator
There is a separate voltage regulator with three wires: yellow, green, black.
Hopefully someone can pinpoint why the battery isn't charging.