SX 125 2004 vs 2005. Where is the difference

[imack]

I have read that KTM detuned the 2004 engine on the SX125 for 2005. My son rides the SX2005, which has plenty of power, but would like to know what is the difference with the 2004 or 2006 model to see if we can reverse the z"detuning" and pack a little more of HP. I am sure that most of it have to do with dimensionsal changes in the cylinder ports. I would appreciatte if someone who may have one of those models or have access to the parts could tell me the dimensions of the top of exhaust and transfer ports to the top end of the bore. If the expansion chamber is different I also would like to know it...!!

Thank you guys..!