Blocks are manufactured by casting and after casting it is machining with high precision machines. Spool meeting are keep inside the block. Spool are guided by two T shape washers in both aspect of the block. And different two items flat washer forces the T shape washer to moves spool ahead and backward.There are several ports are situated bottom of the block and it is marked by A,B,P,T signal.

That first Harley-Davidson differed little from different bikes of the time, CharLynn essentially being a bicycle powered by a simple single-cylinder motor that drove the rear wheel by a leather belt. The conventional pedals and chain remained in place so the rider might pedal the bike up to speed to start the motor, as well as lend slightly leg energy when ascending hills.

The valve plate is hooked up to a steel strut, which is linked to an hydraulic piston and a steel beam. Pressurized oil is directed into the hydraulic piston, inflicting it to maneuver with nice power. This in flip moves the metal beam to which the valve plate is attached back and forth.