The Screw,cross 5x10 is the lowest priced item on this Crankcase - Oil Pump schematic.
Parts such as the Crankcase - Oil Pump: Gasket,crank Case (mca), Washer,spg.,5mm, Knock,dil Pump, Pump Assy,oil are included in the St50 Dax European Direct Sales Crankcase - Oil Pump parts fiche.
This CRANKCASE - OIL PUMP assembly utilises four Screw,cross 6x65(s) - the highest specified component.