25 is provided for each bank 20 a pair of stroke adjustment mechanisms 100 are also provided for each bank 20 the pair of stroke adjustment mechanisms 100 operate collaboratively to adjust the throw of the respective crankshaft 15 by adjusting the throw of the crankshafts 15 the hydraulic machine is provided with variable displacement in other words the swept volume can be increased or decreased by changing the stroke length of the cylinder assemblies 50 thus the hydraulic machine 1 has a stepless ratio transmission throughout the entire speed range two main bearings 105 one at each end of the crankshaft 15 contain the stroke adjustment mechanisms 100 consequently the main bearings 105 cannot be used to transmit torque to transmit output or input torque depending on the mode of operation of the hydraulic machine 1 it is necessary to collect the torque at each main bearing 105 this is achieved using lay shafts 110 see fig1 in the preferred embodiment two lay shafts 110 are used the lay shafts 110 have pinion gears 115 each of which engage a bull gear 120 attached to each of the main bearings 105 the lay shafts 110 collect the torque from the bull gears 120 and also serve to maintain the synchronisation between the bull gears 120 in order to control the stroke length of the pistons 85 a helical shaft 125 is coupled to the bull gears 120 the helical shaft 125 is not used to transmit torque but remains in synchronisation with the bull gears 120 for each bank 20 of cylinder.