In reference to Harley Davidson hand controls, what is a 9/16'; bore?

In reference to Harley Davidson hand controls, what is a 9/16'; bore? Is it a reference to the size of the brake reservoir, brake cable connection or handlebar size? Thanks!In reference to Harley Davidson hand controls, what is a 9/16'; bore?
Actually,,it refers to Master Cylinder Piston Bore.





The hole where fluid exits the M/C has nothing to do with it.





To determine what size you Have,,,You must check the size from the LEVER side of the master cylinder,,,opposite where the hose connects





See here:


http://www.bikebandit.com/assets/schemat鈥?/a>


(hover Mouse on the pic,,,and a Zoom button will appear--click to enlarge the pic)





All the Items encompassed by ';Item #160'; are a master cylinder rebuild kit';





The Piston is in the center of that assembly,,,with the pin-looking thing on it.





The Diameter of that piston is what ya need to knowIn reference to Harley Davidson hand controls, what is a 9/16'; bore?
it refers to the diameter of the hole that brake fluid goes through from the master cylinder as it travels to the brake caliper. larger bore is usually for dual disk, smaller bore for single disk.
.562 Dia.