I just finished doing flax with my 9770 and 630 Draper. Up to five mph. The only pproblem I had was when I took in a wad of threshed flax straw that broke the concave adjusting motor and the shear pins. Replaced the shear pins, adjusted the concave to where I wanted it and held it there with vicegrip pliers.
Incidentally, the motor was one I had previously broken in canola. I had super glued it back together. I'm sure it would have worked had I not put the wad of flax straw in.
On another note, I was doing wheat today testing 18% moisture at 4.6 mph. Rotor 1080, concave 19, fan 1050, chaffer 14, sieve 6,
pre-cleaner 4 turns open, calibration sensitivity 55, great sample
cover plates on centre concave, Loewen Low Wire, Narrow Space Front Concave. Customer was doing 2 mph with his 9600, cracking grain, he was quite impressed with the job we were doing.
This is my 26th year doing custom work locally here in western Manitoba. Canada. I charge $190.00 per separator hour for belt pickup work, plus $6.00 per acre when cutting, customers fuel and trucking.
If you want to do a good job threshing wheat with a Deere STS,
you have to open that concave and speed up the rotor.