Corn coming into the cleaning fan usually means that the bottom seive is set too tight. Is there clean corn going back up tailings? This would be another indication that the bottom seive is set too tight. If you have grain seive in bottom you will have to run it almost open in 200 bpa corn. Grain seive has very short fingers. Are you losing corn out the back over rotor or seive? If it is over the seive then it is probably set too tight also. Fixing rotor loss depends on what you are running for set up. If you have not got any wires pulled out of concaves, you will likely need both sets of straight bars on the back of rotor, or else retard all veines. If you don't have any straight bars on rotor, I would suggest putting at least one set on. You are running keystock grates right? Make sure if you are in damp conditions that concaves and grates are not plugged either.
OLD DAYS CORN IN FAN MENT FAN WAS not running fast enough. Might try with enginean machine at running rpm setting fan speed up until it blows corn out . Also open top sive some more an mavbe close bottom small amount.
Yes open your bottom seive and make sure you are running on the fast side of your clean grain chain sprocket. If you've never done so you have to loosen 2 3/4" bolts and slide the sprocket over. This has always helped me. You may try opening the front section of your top seive also to let the grain fall straight though to your clean grain auger.