last year I was running a 1440 without disruptors and, no matter how much we speed the rotor up or tightened the concave, the green beans gave us a fit tons of power robbing rotor rumble, barely could get over 2 mph with a 15' head. This year we installed new keystock grates, disrupters, and green maize bars. Needless to say different machine, I feel like we added 50 hp to motor. I have been cutting beans with half the leaves on at 3.5 mph and no rotor rumble, last years machine would not even touch them. They do a great job sizing up the green stems and when the beans get dry I could swear the machine has a straw chopper. Replace all the parts I mentioned, which will run about $1000.00 and you'll swear you would pay $2000.00. The only problem I have is I need a bigger head my poor 15' 820 will only do a good job up to about 4 mph, a 17.5' would probably be perfect.