An adjustable vane system (78) for use with a rotor cage of a threshing system (24) of an agricultural harvester (10). The vane system (78) includes a vane (82) having a generally helically curved inner profile (130)； a surface (132) being an outer profile (132) that is opposite the inner profile (130) and is generally helically curved over a portion of the vane (82)； a first flat portion (126) proximate an end of the vane (82) on the outer profile； and a second flat portion (128) proximate to another end of the vane (82) on the outer profile (132).
