Mark, might try slowing cylinder down a bit, we used to run our M2 with widespace Gleaner bars at 350 to 400 and about 3_4 concave clearance. We always felt running at enough speed to thresh properly with out damaging the crop. If your corn is dry run slower, 16 any up speed up a bit. We used to set clearance about 3_16 closer than diameter of average cobs and worked really good for us. Check your two rasp bars also, they tend to wear more in the belly than the sides, the sides may be tighter than you think, one is on the trailing edge of the door and the other right behind it in the feederhouse. Good luck