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.