[suicideneil]

Real neus ( 15xx series ) have large holes in the endbells for cooling ( they are airplane & heli motors ), castleneus are sealed.

Opening up the castle motors is easy though, just undo the screws holding on the endbells, extract the rotor with some pliers, tap out the bearings; reverse order to reassemble it. Dont loose the shims & spacers on the shafts, and just be sure to hold the rotor tightly ( mole grips might be best ) so that it doesnt shoot back inside the motor and damage anything- magnetic attraction is very strong..