We use to pull the sieve (bottom) completely out on smaller combines with capacity problems in corn and just use the chaffer(top) for cleaning, so this guy is correct with his recommendations.
The top seive is much easier to throw grain out of the back of the machine as anything not getting through it exits the machine, the lower one only dictates what gets to the tank and what ends up getting rethrashed, keep this in mind as you set the upper chaffer seive, to far closed and you will put kernels on the ground behind the machine.
The cleaning system in the S Series directs the majority of the air directly at the Chaffer(the top sieve), there for the sieve does not have that big of an effect on air in this newer cleaning system. But I agree on opening the bottom sieve up to the point of little to no returns, and cleaning with the chaffer.
We thought we had a problem in our concave settings breaking cobs in half...turns out our header was breaking them in half at the front cross auger. Just a slight break that turned into a full break by the feed accelerator, making threshing difficult...which appeared as rotor loss.
Good question: To fully address your question, feel free to call Marion on his cell phone at (309) 368-1182. Also, you can visit our combine settings page at calmercornheads.com/in-the-field/combine-settings
