Parts such as the Wire Harness - Horn - Ignition Coil: Nut,flange,6mm, Coil Assy.,ign., Coil,r.ignition, Bracket B,ign are included in the Cb550f2 Super Sport 550 Four 1977 Australia Wire Harness - Horn - Ignition Coil parts fiche.
On this parts fiche the Band A1,wire is the most specified component.
The component with the lowest price in the WIRE HARNESS - HORN - IGNITION COIL schematic is the Screw,pan,5x20.