Rectifier

Have 1980 kz750 h1 rectifier has the connector and one wire that goes to the positive on the battery separate from the connector... When I unplug it stop seeing the voltage go up on the voltmeter but the bike seems to idle better I tried another rectifier from my parts bike and has the same effect... I think that be what my bike dieing out problem is...can that mean the stator is bad...

What are you getting for output voltage with it connected and without it connected?

Reg-rec connector unplugged = stator disconnected: no stator connection, no charging.
The bike keeps running because the battery is supplying the DC voltage.
With the reg-rec connected the voltage should be approx. 14.5 VDC @ 4,000 rpms.

FYI: the separate red (or red-white) power wire goes to the hot side of the starter solenoid.

12.7 without 13.7 with it

I can't see were 4000 rpm is being have no tach

Also hood thing u said take connectors off just noticed three I haven't changed yet their pretty brown cause I had few other connectors same way we're hot to touch... I'll change them out get back

Hot to the touch and turning brown from heat are obviously not good. High resistance connections can cause all sorts of problems. I wouldn't expect it to fix your problem but also I don't know any good reason that disconnecting the charging system would cause the bike to run better...

koloj wrote: I can't see were 4000 rpm is being have no tach

I would set up a couple of fans to blow air across the header pipes & engine,
then rev it up to see what the voltage does. I don't think it should go much above 14.5 VDC.
Maybe 15.1 VDC max??? If you rev it to about 4k & it stays around 14.5, then the charging system is probably okay.

I would go aheads & check the stator: make sure the battery is charged, disconnect the 3 yellow stator wires, set the multimeter to AC voltage, start the engine, then check the 3 yellow stator wires in pairs (3 measurements) -->> you should get about 50 VAC @ 4000 rpms.