How to Tune an RC Motor

Open the motor. Remove the two end screws in the plastic end-bell. Once these are out, pull the can away from the end-bell, then pull out the armature. The armature is the metal rod with wire wound around it. Remove the plastic shims from either end of the armature and set them aside.

Rub permanent marker over the entire surface of the commutator, then sand it with a sheet of 2000 grit sandpaper until all of the ink is gone. To make things easy, insert the metal rod into a dremel, and spin it rapidly while you apply pressure with the sand paper. Once the commutator is smooth, insert the commutator end into the dremel, then sand the metal rod with a sheet of 2000 grit sandpaper until smooth.

Press the bushings out of the motor can. There are donut-shaped bushings located at the points where the armature contacts the front of the can and the plastic end-bell. Use a screwdriver to press the bushings free. Take care while handling the bushings as a minor dent will drastically decrease the motor's performance.

Clean the bushings. Put some cheap toothpaste onto an old armature, insert the opposite end into a dremel. Slide the bushings onto the toothpaste end, then engage the dremel for a few minutes. Apply more toothpaste to keep everything lubricated. Rinse the bushings clean once finished.

Allow the bushings to sit long enough to air dry, then rub them over with a piece of 2000 grit sandpaper until they're shiny smooth and practically frictionless.

Apply lubrication to both ends of the armature's shaft. Make sure not to overdo it, since getting any on the commutator will affect the motor's performance.

Insert the bushings back into the motor can and end-bell. Slide the front shaft of the armature back through the front of the motor can. Insert the backside of the shaft into the end-bell, then press the end bell firmly against the can to reinstall the screws. Spin the motor shaft to ensure that the device is rotating smoothly.