On this parts fiche the Circlip-piston Pin is the most specified component.
This schematic depicts all components used in the A1ss Samurai 1967 Europe Usa Crankshaft/pistons A1/a1ss partslist.
The Crankshaft/pistons A1/a1ss is made up of components including this Crank&conrod Assy which is the most expensive.