I wasn't very happy with the standard Prusa Y motor mount due to it's lack of rigidity (I used a cable tie on the back of the motor for extra support until now.) Since I am running Synchromesh Cable now and not belts (see http://www.thingiverse.com/thing:15923 ) and the cable is so thin I figured there was no need for an idler pulley above the motor. This eliminates one bearing and some nuts and washers and also helps your pulley get a better grip on the cable because it wraps 3/4 around rather than about 1/2 with the original motor mount.Simply print, remove your old Y motor mount and the idler and put this one in it's place (it is a pain because you have to un-thread both front rods, but it is worth it for the improved quality.) Enjoy the excellent pulley-to-cable connection!