1420 Milo Settings

rotor 450, fan max, concave 3, top sieve half inch, bottom sieve quarter inch.

I also put vanes in slow position over the grates

Fan max???? I would've had an empty grain tank. Here's what worked for me. Rotor 700, fan 600, and concave on hard thresh. I think this milo may have been really low test weight hence the low fan setting and high rotor speed.

In the past I have run the fan at 1000-1100 rpm and blown nothing out the back except for a few immature seed. But then again my crop and conditions from past years may be completely different from yours. Even so, your fan speed does sound low even with light grain. I would try increasing the wind and opening the very back part of the chaffer almost wide open. May work or might not but worth a try

It is very hard to blow grain out the back of an axial flow. I used maximum fan because it was the only way I could clean it up to an acceptable level. I was losing hardly any grain. I still think your rotor speed is way too high. I was cracking grain anytime I got over 450.