On this parts fiche the Bolt(6x39) is the most specified component.
The Suzuki CYLINDER HEAD has thirty-three products enlisted in the schematic.
Parts such as the Cylinder Head: Ring,snap, Bolt, O Ring(d:2.4,id:39.7), Plug,spark(u24etr) are included in the Gsx600f Katana 1999 (x) Usa (e03) Cylinder Head parts fiche.