Abstract: Adjustment of the sieve of a combine harvester is effected by an adjustment apparatus attached to the side wall of the combine on the outside surface. The adjustment apparatus comprises an angle bracket having a vertical portion screwed to the side wall and a generally horizontal plate. The lever is pivotally mounted to pivot in a plane parallel to the horizontal plate and is maintained in place by a top strap having an arcuate series of holes for pinning the lever at a selected position. A rod extends from the end of the lever through a slot in the side wall of the combine to an adjustment arm extending rearwardly from the sieve. The adjustment position of the arm can therefore be locked in place and is visible from the outside of the combine.