Abstract: A variable displacement bi-directional hydraulic motor 10 comprising a rotatable member 14 that has an axis of rotation and defines a plurality of cylinder bores, respective pistons 30 received in said bores and a yoke 34 provided with a bearing surface that is engaged by respective bearing members 32 carried at an end of the pistons that projects from the cylinder bores, said yoke being mounted for pivoting movement about a pivot axis to allow a swash angle of said bearing surface to be varied, whereby the displacement of the motor can be controllably varied and the direction of rotation of the motor can be changed and the arrangement being such that said bearing surface is inclined at a fixed angle in a plane perpendicular to the plane of said swash angle.