The Yb100 1987 18n England 2718n-310e1 Fuel Tank consists of fifteen pieces with the Fuel Tank Comp. being the most expensive.
Some items from this specific schematic: Gasket, Nut (nas), Damper, Locating(3), Damper, Locating(1), Emblem, Fuel Tank (r.h).
The component with the lowest price in the FUEL TANK schematic is the Screw, Pan Head.