On this parts fiche the Bolt,flange,6x55 is the most specified component.
Parts such as the Front Crankcase Cover(trx 500fm/fpm): Nut,hex 8mm, Plate Comp,clutch, Arm Comp,sub Gear, Rubber,filter are included in the Trx500fmb Trx500fm 2011 (b) Australia Front Crankcase Cover(trx 500fm/fpm) parts fiche.
Of all the components used in this assembly the Cover Comp,fr Cra is the most expensive.