dear u forget that both are different technologies
1-CG 125 is 4 Stroke
2-GTO and RX are 2 Stroke machines
what is 4 Stroke;
in this type 3 strokes are idle strokes and only one stroke is usefull stroke it mean this type of engine produces power after the 2 revolutions of crank shaft.
What is 2 stroke:
in this type of engine every 2nd stroke is usefull and on the completion of each revolution of crank we can get power.
thats why torque production in 2 stroke is more then any same capacity 4 stroke engine.