The E-15 Primary Shaft assembly is constructed from several parts from which the Sprocket,primary is the most expensive.
Some items from this specific schematic: Bolt,flange,6x16, Outer,stat.clutch, Sp,start.clch.rol, Shaft,primary.
The component with the lowest price in the E-15 PRIMARY SHAFT schematic is the Bolt,hex., 6x16.