Of all the components used in this assembly the Head Assembly,cylinder is the most expensive.
Parts such as the Cylinder Head: Net,intake, Gasket(14x19.2x2) (nas), Guide,valve, Pipe,oil No.1 are included in the Gsxr1100 1990 (l) (e01 E02 E04 15 16 17 18 21 22 24 25 34 39 53) Cylinder Head parts fiche.
On this parts fiche the Bolt(6x39) is the most specified component.