A threshing system for use in an agricultural harvester, the threshing system comprising: a rotor cage with a plurality of slots therein, the rotor cage having an outer generally cylindrical surface; a plurality of banks (84, 86) of adjustable vanes pivotally coupled to the rotor cage including a first bank of vanes and a second bank of vanes; and an adjustable vane control system coupled to the rotor cage; characterized in that the adjustable vane control system includes: a first member pivotally coupled to each of the vanes in the first bank of vanes through corresponding ones of the slots; a second member pivotally coupled to each of the vanes in the second bank of vanes through corresponding ones of the slots; a first linkage; a second linkage; and an arm having an end that is coupled to the first member by way of the first linkage, the arm having an opposite end that is coupled to the second member by way of the second linkage, the first member and the second member each having a range of travel defined by the slots, the first member and the second member each having a surface facing the outer surface of the rotor cage, the surface of the first member and the surface of the second member each remaining tangent to the outer surface of the rotor cage as the first member and the second member are moved within their range of travel. a rotor cage with a plurality of slots therein, the rotor cage having an outer generally cylindrical surface; a plurality of banks (84, 86) of adjustable vanes pivotally coupled to the rotor cage including a first bank of vanes and a second bank of vanes; and an adjustable vane control system coupled to the rotor cage; characterized in that the adjustable vane control system includes: a first member pivotally coupled to each of the vanes in the first bank of vanes through corresponding ones of the slots; a second member pivotally coupled to each of the vanes in the second bank of vanes through corresponding ones of the slots; a first linkage; a second linkage; and an arm having an end that is coupled to the first member by way of the first linkage, the arm having an opposite end that is coupled to the second member by way of the second linkage, the first member and the second member each having a range of travel defined by the slots, the first member and the second member each having a surface facing the outer surface of the rotor cage, the surface of the first member and the surface of the second member each remaining tangent to the outer surface of the rotor cage as the first member and the second member are moved within their range of travel. a first member pivotally coupled to each of the vanes in the first bank of vanes through corresponding ones of the slots; a second member pivotally coupled to each of the vanes in the second bank of vanes through corresponding ones of the slots; a first linkage; a second linkage; and an arm having an end that is coupled to the first member by way of the first linkage, the arm having an opposite end that is coupled to the second member by way of the second linkage, the first member and the second member each having a range of travel defined by the slots, the first member and the second member each having a surface facing the outer surface of the rotor cage, the surface of the first member and the surface of the second member each remaining tangent to the outer surface of the rotor cage as the first member and the second member are moved within their range of travel.