As torriem said, CR’s & Case share the same cleaning system (pre “Opticlean) albeit the fan, shoe drive are different & rethrasher is different.
In theory, the Case fan should be much better than the “old paddle fan” of a CR! Well, it’s not the fan that’s the problem.
I tried the inverse sieve settings & never got any satisfactory results.
To cut a long story short.
Make sure the concave is LEVEL & CENTRE first. Can’t stress how important this is to get this right. It’s in the operators manual & it’s 87mm for Level & 87mm for Centre .... AFX Large Tube rotor.
Make sure you have very good concaves in #1. I’ve found deep wire helicals work best in #1 for just about every crop. Cereals, canola, pulses etc.etc. These work.
If you haven’t yet done so after harvest, pull all the sieves out & clean the rails. Check all sieves are not worn out or broken any louvre wires. 1200-1400hrs is all you’ll get out of sieves.
Refit bottom sieves & make sure they open - side to side - evenly. Adjust as required, then calibrate them.
Fit top sieve rear curtains before refitting top sieves. Adjust sieves as required, then calibrate.
These curtains make a big difference to a machine that is set & calibrated correctly. The curtains make the air go through the sieves instead of going out any area that has the easiest exit.
You’ll find a much more “settled” & consistent machine once you done these things.
It’s no bullshit ..... they work ....... & it’s cheap to do.
Happy to discuss further if you want........ but all these other things MUST be done first. There’s no one “silver bullet” in making machines perform better. It’s incremental steps that get you there.