An hydraulic centrifugal piston motor having mulitple piston circumferentially disposed at right angle to shaft axis, having a rotational power moment that occurs twice each revolution for each cylinder. The power stroke for each cylinder would occur for a duration of 90 degrees twice during each 360 degree operating cycle. Hydraulic input is applied to opposing pairs of cylinders and overlap of successive power strokes provide rotational balance and cancels net reaction forces applied to the bearings. Another feature of the motor would be the particular design of the power transfer device. The thrust of the power transfer device is applied axially to the drive shaft providing a smooth transfer between the hydraulic input power and the mechanical output power.