Mystery wire 84 GPz 550

Thanks for response, reading up I figured I didn’t want to start aimless prodding to see if it could work.

I’ve been looking at some listing for the correct part. Some catalogs aren’t updating with correct photos, so I’ve been a little uneasy to incorrectly buy again.

Like Martin mentioned, you will want a reg/rec for a 1-phase (2 yellow wires) system. The 1980 Kz550 was the first year 550 in the U.S., and it was the only year that came with a 1-phase charging system. After that, all 550's came with 3-phase (3 yellow wires) systems. Most aftermarket reg/rec companies ignore the 1-phase model and assume all years had 3-phase.

By GatlinM: .... I’ve been looking at some listing for the correct part. Some catalogs aren’t updating with correct photos, so I’ve been a little uneasy to incorrectly buy again.

You could ask the sellers if the unit in question is for single phase or 3-phase. and also ask how many yellow wires. Also, some modern reg-recs have the voltage sensing built into the circuitry, so they won't have a brown wire, but there will be a power wire & ground wire (the colors vary). Rick's electric specifies that the 10-304 is for single phase. For good used, you might be able to use an oem voltage regulator from a modern motorcycle, but I don't know if any models would have a single phase. I'd guess a smaller motorcycle.

The 1978 and 1979 Kz650 models used 1-phase permanent-magnet alternators like your 1980 Kz550. So any reg/rec designed for them should work on yours. The only difference would be the brown sensing wire that Martin mentioned. If the reg/rec does not have the brown wire, just leave the brown wire on the harness end disconnected. Make sure it's a regulator and rectifier, though, and not just a rectifier.