TOPIC:

I know a guy who has a KZ650 which has one of the two phase stators (hope I got the terms right). It has two hot AC wires coming off the stator, in other words. He gets 12VDC at idle and about 12.5 VDC at 4K rpm. OK... I know a little about charging issues and this one has me stumped. He has changed stators, rewired correctly and changed regulators. Same issue. He tells me that his regulators have only the two stator connection wires, the black/yellow ground and the hot wire out; I think white/red which tees with the rectifier and goes to the main fuse and battery.

Should there be a sense wire such as a wire to connect to the brown sub-circuit to tell the regulator the voltage level to put out? Other than a sulfated battery, bad stator, bad regulator or bad wiring, any ideas on why this bike won't charge?

The KZ650's from about 78 to 80 (or so) used a single-phase (two-wire) alternator with a reg/rec combo which did NOT use the brown sensing wire. The reg/rec should only have 4 wires. It senses battery voltage through the output wire which goes to the battery.

Because the sense wire is the output wire, it stays connected to the battery all the time. This has a possibility of tiny tiny current draining the battery when the bike is off. I think that is why Kaw went back to the sense-wire system.

Can't say why he's not charging, though. You know the general drill on testing. He's definitely getting zero output. The voltage raises slightly (12 to 12.5) because the ignition uses less power at higher RPMs.

If it's wired correctly, it has to be the reg/rec, stator, or flywheel.