Abstract: An internal combustion engine air cleaner assembly has a lower supporting tray wall, a top cover or enclosure wall, and a side wall, together defining a hollow air expansion chamber containing a filter element; the chamber has an air inlet and an outlet opening to the engine that lies in the plane of the lower wall, the outlet being part of an angled outlet orifice cowl asymmetrically positioned with respect to the centerline of the surrounding side and top walls and surrounding the outlet and having an inlet that is in a plane inclined to the planes of the top and side walls to reduce noise.