fifteen components are listed in the schematic for this Gsx550ef 1985 (f) (e01 E02 E04 E06 E17 E18 E21 E22 E24 E25 E34) Cylinder .
On this parts fiche the Pad,cylinder Head is the most specified component.
Some items from this specific schematic: Cylinder, Washer(10x15x1.5), Bolt,oil Pipe, Clamp,oil Hose Crankcase.