Rotor loss in corn comes from full corn shucks caring kernels out. The removal of wires will deffently help but getting a clean sample comes from he concave. The more square the leading edges are on your concave bars, the cleaner the thrash. Cover plates do two things, first they make the thrashing area smaller so it will load up more and have more material rubbing against material. This is thrashing. With cover plates they also hold the material from the bottom and the straw acts as a cushion for the thrashing action. But good square edges are the best fix to clean up uour sampel. If you are running a specility rotor, The Disrupter is your answer for rotor loss. Install 9 Disrupter lugs in the grate section and 32 Rice spike bars on the rotor. You must revove all of the retarder bars ( either 4 or 8 on 80 series or 3 0r 6 0n 60 series) The rice spike bar will swing within 1_8 of an inch from the disrupter lug to cut up the corn shuck that is carring your crop out.. They will also cut up your green stem bean straw. Call me if you like at 1-800-235-4461 Estes Mfg. Co. ask for Don. I have some other tips as well.