On this parts fiche the Clamp, Breather Tube is the most specified component.
Parts such as the Air Cleaner ('78-'79 Kl250-a1/a1: Screw-pan-cros,5x25, Clamp, Breather Tube, Element-air Filter, Nozzle are included in the Kl250a2 Klr250 1979 Canada Air Cleaner ('78-'79 Kl250-a1/a1 parts fiche.
The Air Cleaner ('78-'79 Kl250-a1/a1 assembly is constructed from several parts from which the Air Cleaner Assy is the most expensive.