What the heck is this? 78 KZ1000

The thing with all the goofy connections is the rectifier. It converts the AC output of the stator to DC for the electrical system.

Later, Doug

Will I need this hooked up for a hot wiring? I just want to see if it runs good

It converts the AC from the generator to DC. Without it, your electrical system will be using AC. It will, as a minimum, chew up your battery, overheat your coils, and screw up almost anything else that is hooked up. It will also fry your Dyna-S.

I'd say "Yes, you need it,"

I do have a whole harness. I think it's uncut............

How can I test to see if its bad? Or basically, how do I know if its good? Also, it has a black wire coming out of it beside a bit heavier white wire. The black wire is cut. Is this a chassis ground or does it go to something else?

HAFROD wrote: How can I test to see if its bad? Or basically, how do I know if its good? Also, it has a black wire coming out of it beside a bit heavier white wire. The black wire is cut. Is this a chassis ground or does it go to something else?

Search the filebase section of this site for wiring diagrams. There are diagrams for the 78 A2, B2 (LTD), and D1 (Z1r). I see from another post that your bike is a bit of a hybrid.

Based on these diagrams the rectifier should have three yellow wires that come from the alternator, a white wire that goes to the positive battery terminal, and a black wire that goes to chassis ground. On the z1r the black wire is drawn as connecting straight from the rectifier to the chassis. On the A2 and B2 it's shown passing through the 6 pin connector along with the yellow wires. Once through the connector the black wire changes to black/yellow, and runs to the negative battery terminal.

As for testing the rectifier, I can't think of an easy way to do it. Do you have a volt meter that includes a diode test function? This would be a good place to start.

Does anyone have an opinion about what would happen if you just disconnected the alternator stator coil and left it unplugged while running the engine? I was thinking the engine would run fine just on the battery. But I'm worried that leaving the stator coils open/unloaded could cause a high voltage that would damage the stator.