This Carburetor Assy. is the most expensive of the items that make up this Carburetor Assy. (link) assembly.
In this schematic the "Screw-wash. 5x12" is used most often.
Parts such as the Carburetor Assy. (link): Rod Set, Pump, Carburetor Assy. 4, Carburetor Assy., Screw Set B are included in the Cb750sc Nighthawk 750 1983 (d) Usa Carburetor Assy. (link) parts fiche.