Parts such as the Cylinder Head: Cylinder Head Assy, Plug Spark (ngk Cr6hsa) Ur, Nut, Crown (4g0), Washer, Plate are included in the Ttr90 Offroad 2002 (2) Usa Cylinder Head parts fiche.
In this schematic the "Washer, Plate" is used most often.
The Screw, Pan Head(3tj) is the lowest priced item on this Cylinder Head schematic.