We struggled last season to get our 2188 to quit throwing grain out the back, wheat, soybeans. We're pretty sure it was out of the rotor. We use caseih small and large wire concaves in wheat and beans, respecitively. We did find that removing some wires in the second and third concaves did help. We also run slotted grates in wheat and keystock in beans. Have 30' head in wheat 60-100bu/a. and 35-65bu/a beans. We run with a 9510 and 9610 JD's and are the worst performer of the three. Any suggestions? Read a lot about cover plates and different concave and grate configurations, is that what i need?