4 stroke dirt bikes steer with more weight on the front wheel while two stroke handle with the rear, this is more of power characteristic than motor placement. This is why four strokes are horrible on loose/harsh conditions. MXA quoted the 2012 yz250f to have road racing qualities for this exact reason. This is why tracks are flatter now than they were in 05.. Another problem is the high center of gravity there for adding more of a weighted feel in turns, this is why we don't have deep berms any more. The whole idea of a twin overhead cam let alone single 4 stroke dirt bike is redonculous. For the evolution of dirt bikes, it sure seems like we're going the wrong way.