Check out any of the eight Cylinder components enlisted.
Parts such as the Cylinder: O-ring,78.3x2, Gasket,cylinder (nas), Cylinder Comp., Dowel,pin,12x20 are included in the Trx250 Fourtrax 250 1987 (h) Usa Cylinder parts fiche.
This CYLINDER assembly utilises two Dowel,pin,12x20(s) - the highest specified component.