I removed my cage sweep on our N-6 last harvest. In cereals i found I needed to run the covers on the sections of just above the concave and the next section over on the separator side. This is the area that the cage is closest to the back wall and straw will hag up there. For Canola and lentils I remove all covers and works fine. Also helicals have to be in good shape, we installed the channel helicals from NDDan. This keeps the straw moving and not getting broken up and pushed through the cage. If your cage area is getting plugged up I think you have to be losing separating area.