Originally Posted by Davidka

4-stroke has real potential if it's ever properly developed. There are a few misconceptions here:

It is not true that 4-stroke is less powerful than 2-stroke of the same displacement. While that's generally true (especially in our model engines), in motorcycle racing it's no longer the case. A pro level 450cc bike makes more hp than the 500cc 2-strokes used to, same is true of the 250ccx4 vs. 250ccx2 and MotoGP. 2-stroke engines were developed to the point that they were not finding ways to make them appreciably faster from year to year. All of them are spinning more RPM than a 2-stroke will ever be capable of now because they've figured out how to prevent valve float. The main reason our model engine 4s engines don't spin fast is because it's not usable for airplanes. There is a maximum usable speed for propellers.