Sounds like you have an early JDM 185? It has the same front brakes as an ST165.
ST165 Front R 2 pot brake: 47730-20240
Early JDM ST185 Front R 2 pot brake: 47730-20400
Early JDM ST185 Rebuild Cylinder Kit: 04479-20110
Looks like those numbers are all discontinued. Might have luck with www.amayama.com
If you can only find the 1 pot later model ST185 brakes, it might be worth considering changing to them. They may only have 1 pot, but they have larger rotors.