The component with the lowest price in the F-10 DOUBLE SEAT schematic is the Bolt,hex., 6x16.
Parts such as the F-10 Double Seat: Bolt,hex., 6x16, Lever, Seat Catch, Collar,seat.hook, Spring Seat Catch are included in the Cb250k3 F-10 Double Seat parts fiche.
With nine applications this Washer,spring,6mm is the most specified part.