The lever will travel twice as far, because it's actually the piston seals that dictate how far the piston moves. The slot the seal site in is this sort of shape |_/ so when you pull the lever, the piston moves in and the seal flexes over onto the slanted edge, if the pads need adjusting closer to the rotor, the seal flexes over and the pistons then slide in the seal, then when it returns the seal flexes back but the pistons stays in the new position in the seal. The lever has a valve which opens as you release the lever and sucks more oil into the system. (I think). Basically the lever will travel twice as far towards the bar, so it would be pretty useless.