A combine harvester comprises a threshing and separating mechanism mounted to a main frame, which includes a generally cylindrical chamber having a generally longitudinal axis, and a separating concave assembly. The arrangement further includes a rotor assembly mounted for rotation in the chamber and comprising a generally cylindrical rotor body with a separating section associated with the separating concave assembly. The separating mechanism further comprises a beater assembly arranged behind the concave assembly for receiving threshed and separated crop material therefrom and projecting it rearwardly. The beater assembly comprises a transverse guide mounted behind the separating concave assembly and below the rotor body, and a transverse beater rotor. The chamber comprises a curved guide plate arranged behind the separating concave assembly and above the guide. This guide plate distributes the separated crop material over the full width of the guide in order to minimize the chance that material starts accumulating in the one or other corner and the separating system gets plugged.
