The Bolt-flanged,8x12,bla is the lowest priced item on this Cowling(zx550-a1/a2) schematic.
The thirty-four Zx550a1 Gpz550 1984 Europe Uk Fr Gr It Fg Sd St Cowling(zx550-a1/a2) component parts are all listed in this schematic.
With ten applications this Nut,flanged,6mm is the most specified part.