The Crankcase is made up of components including this Set-crankcase which is the most expensive.
On this parts fiche the Bolt-flanged-small is the most specified component.
Parts such as the Crankcase: Bolt, Clutch Spr Fitt, Bearing-ball,#6205c3, Oil Seal,tcj20407, Stud,10x65 are included in the Kdx250-b3 Kdx250 1983 Usa Canada Crankcase parts fiche.