The component with the lowest price in the FRAME BODY schematic is the Nut.hex 10mm.
On this parts fiche the Cap,member Side is the most specified component.
Parts such as the Frame Body: Cap,member Side, Mark,battery Cau, Washer, 45mm, Bolt,flange12x308 are included in the Cx500c Custom 1980 (a) Italy Frame Body parts fiche.