A few words about frames of reference.
Newton's Laws hold only with respect to a certain set of frames of reference called Newtonian or inertial reference frames.[1]
The first Newton's law is: "Every body remains in a state of rest or uniform motion (constant velocity) unless it is acted upon by an external unbalanced force. This means that in the absence of a non-zeronet force, the center of mass of a body either remains at rest, or moves at a constant speed in a straight line.[1]
However Newton's laws don't deny free move center of mass of isolated system. Second and third laws describes bodies forces interaction. Otherwise, bodies knows nothing about each other and center of mass of isolated system is meaningless without bodies forces interaction. Base on symmetric bodies forces during interaction, the center of mass of isolated system should hold same position. It's true for simple motions, where force has simple meaning. However, for rotational and translational motion force can have two components from simple motions. In this case, net force may achieve same value by different components variation. For example 3+4=7 and 4+3=7. Where first number is translational force component and second number is rotational angular force by radius projection component. Therefore, center of mass of system for bodies forces interaction in rotational and translational motion can move. Otherwise, bodies during interaction should get additional extra forces from nowhere which will help to hold center of mass of isolated system on same position. Energy for these additional extra forces should come from nowhere too. Unfortunately, the modern classical mechanics equalize holding same position of center of mass of isolated system with symmetric forces for any cases of bodies forces interaction, because rotational and translational motion is a product of sum of two simple motions.
This solution will follow free move center of mass of isolated system for single standalone rotational and translational motion, because no strong description about it in Newton's laws. This solution won't include any additional extra forces to helping to hold center of mass of isolated system on same position.
Refernce:
[1]http://en.wikipedia.org/wiki/Newton's_laws_of_motion
http://knol.google.com/k/alex-belov/the-wheels/1xmqm1l0s4ys/18#
