Combine harvester comprising a combine harvester chassis and a cleaning shoe for separating threshed grain from material other than grain, said cleaning shoe comprising at least one sieve (5, 6, 10) and an associated sieve drive assembly, said sieve (5, 6, 10) being moveable by said sieve drive assembly to perform a reciprocating sieve movement having a sieving stroke and a sieve throwing angle, wherein the sieve drive assembly comprises: - a rotary drive, which rotary drive comprises a rotatable output shaft, - a transmission that provides a connection between the rotatable output shaft of the rotary drive and the sieve, which transmission is adapted to transform a rotational movement of the rotatable output shaft into the reciprocating sieve movement of the sieve, which transmission comprises an eccentric device, one or more transmission elements (31, 32, 33, 34, 40), and a plurality of linkage pivots (50,51,52,53,54,55), wherein the eccentric device has an input that is connected to the rotatable output shaft and an output that is pivotably connected to one of the one or more transmission elements (31, 32, 33, 34, 40) through one of the plurality of linkage pivots (50,51,52,53,54,55), which eccentric device has an eccentricity for inducing movement of the at least one transmission element, and wherein each transmission element (31, 32, 33, 34, 40) is associated with at least two associated linkage pivots (50,51,52,53,54,55), wherein each associated linkage pivot pivotably connects said transmission element with one of: another transmission element of the one or more transmission elements (31, 32, 33, 34, 40), the eccentric device, the sieve and/or the combine harvester chassis, and wherein at least one transmission element is an adjustable transmission element in which the distance between at least two linkage pivots associated with said adjustable transmission element is adjustable in order to adjust the sieving stroke and/or sieve throwing angle, characterised in that the transmission comprises a first non-adjustable transmission element (31, 41) which is pivotably connected to the eccentric device, wherein the first non-adjustable transmission element (31, 41) is further pivotably connected to the adjustable transmission element, which adjustable transmission element is further pivotably connected to the combine harvester chassis, and wherein the first non-adjustable transmission element (31, 41) is further pivotably connected to the sieve through at least one further non-adjustable transmission element (32, 33). - a rotary drive, which rotary drive comprises a rotatable output shaft, - a transmission that provides a connection between the rotatable output shaft of the rotary drive and the sieve, which transmission is adapted to transform a rotational movement of the rotatable output shaft into the reciprocating sieve movement of the sieve, which transmission comprises an eccentric device, one or more transmission elements (31, 32, 33, 34, 40), and a plurality of linkage pivots (50,51,52,53,54,55), wherein the eccentric device has an input that is connected to the rotatable output shaft and an output that is pivotably connected to one of the one or more transmission elements (31, 32, 33, 34, 40) through one of the plurality of linkage pivots (50,51,52,53,54,55), which eccentric device has an eccentricity for inducing movement of the at least one transmission element, and wherein each transmission element (31, 32, 33, 34, 40) is associated with at least two associated linkage pivots (50,51,52,53,54,55), wherein each associated linkage pivot pivotably connects said transmission element with one of: another transmission element of the one or more transmission elements (31, 32, 33, 34, 40), the eccentric device, the sieve and/or the combine harvester chassis, and wherein at least one transmission element is an adjustable transmission element in which the distance between at least two linkage pivots associated with said adjustable transmission element is adjustable in order to adjust the sieving stroke and/or sieve throwing angle, characterised in that the transmission comprises a first non-adjustable transmission element (31, 41) which is pivotably connected to the eccentric device, wherein the first non-adjustable transmission element (31, 41) is further pivotably connected to the adjustable transmission element, which adjustable transmission element is further pivotably connected to the combine harvester chassis, and wherein the first non-adjustable transmission element (31, 41) is further pivotably connected to the sieve through at least one further non-adjustable transmission element (32, 33).