In this schematic the "Pin, Dowel B (664)" is used most often.
Parts such as the Crankshaft. Piston: Washer, Plain (646), Washer Plate 648115870000, Cir Clip (656), Piston (0.50mm O/s) are included in the 40mhz/trz 2001 Crankshaft. Piston parts fiche.
The most reasonably priced component used on the 40mhz/trz 2001 Crankshaft. Piston is the Washer, Plain (646).