On this parts fiche the Bolt,flange,6x35 is the most specified component.
Parts such as the Crankcase: Drain Cock, Crank Case Comp,r, Screen,oil Filter, Bolt,socket,6x20 are included in the Trx350d Fourtrax 1987 (h) Italy Sul Crankcase parts fiche.
The eighteen Trx350d Fourtrax 1987 (h) Italy Sul Crankcase component parts are all listed in this schematic.