Because four-stroke engines have their strokes separated by mechanical valves, they avoid two-stroke exhaust gas dilution. So as soon as the rider moves the throttle, the engine begins to fire, giving a very small amount of power. This is “the close relationship between the throttle and the back tire” of which Rossi spoke. This made the defensive point-and-shoot riding style unnecessary, so GP riders advancing from 125/250cc GP classes no longer had to forget everything they had learned to adapt to big bikes. In 125, there is too little power to make up a large loss of speed in corners, making high corner speed essential to good lap times. This was also true in 250, which is why in the 500 era we saw some 250 riders fail to fully make the transition to 500. Riders cannot just change their styles because it is a good idea; style is the complex set of reflex loops that are the only safety the rider has. Changing them would be like learning to walk all over again.