K&N Filter Round / Conical Air Filters

Most of K&N’s round listings are for engines with a round air cleaner on top of the carburettor or throttle body. Round Air Filter Assemblies and Custom Racing Assemblies are complete units, each with a base, a filter element and a top plate. K&N describes them as suiting any engine that uses a round element air cleaner housing. Some have chrome top and base plates, others a carbon fibre top. The E-series round, oval and rectangular filters are drop-in replacement elements, for when you keep an existing housing.

A smaller group is made for twin-choke carburettors such as the DCOE and DGV types, listed with the flange size in millimetres.

Size decides the choice. The listings that give dimensions quote the outer width and the height, for example an outer width of 133 mm. Check the headroom under the bonnet before picking a taller element, and measure the carburettor or throttle body neck for the base. Make sure the base plate seals fully to the carburettor flange, because any gap lets unfiltered air straight into the engine.