We are running a 01' 2388 (new to us this year) with full gordon bars, 3 skip wire large wire concaves, keystock grates and an aftermarket sieve ( not sure what make they are, The chaffer is unadjustable and is made up of 5 inserts with oblong "D" shape holes.) And the shoe is a plastic type short finger. We are harvesting 26% 180-200 bu. corn and cannot keep from overloading the tailings over 3 mph with an 8 row head. The rotor is running 300 and the concave at 6 ( we are also having issues with griding the corn) and fan at 1300. The shoe is wide open and we cannot keep the tailings in check. I have checked and it's not the sensor or indicator playing games. The grain loss is acceptable and we are getting a good sample with more fines than i am used to seeing but in this area everyone is having the problem i am hearing. The tailings don't make sense to me.