Abstract: A cyclone reservoir for separation of an aerated portion of a hydraulic fluid and a related method of making the cyclone reservoir. The cyclone reservoir includes a lower chamber having a generally cylindrical side wall, a return port, and a suction port. An upper chamber is connected to the lower chamber by a neck section that places the interior volumes of the lower and upper chambers in fluid communication with one another. The neck section has a cross-sectional area taken perpendicular to a central axis of the reservoir that is smaller than a cross-sectional area of the lower chamber and the upper chamber at a different position along the central axis. The chambers and neck section may be made as a single-piece part by molding the reservoir by, for example, rotomolding. A reinforcement band may also go around the neck section to connect and support the upper and lower chambers.