In this schematic the "Pipe,water Inlet" is used most often.
Parts such as the Water Pump: Bolt Flange 6x12, Clamp,water Hose, Pipe,water Inlet, Bolt,flange,6x95 are included in the Gl1500c Valkyrie 1999 (x) Australia / Rbm Water Pump parts fiche.
The Water Pump is made up of components including this Pump Assy,water which is the most expensive.