You do not need a thrust washer puller or hub puller to change out the bearings in a RC model engine.
Here is how you do it.
http://rcmodelreviews.com/bearings.shtml

if the engine is working fine, and you haven't done something to it to warrant taking it apart to inspect, you really want to leave it alone.
The piston wears into the cylinder and the microscopic grooves in the cylinder and piston match up for a perfect fit. When you pull the cylinder out, you cannot get it back in exactly the same way as before, so now the piston fit is not perfect anymore. So you'll need to break it in again. Sometimes you wind up with a slight performance loss, sometimes no power is lost. it depends.