Originally Posted by Roelof

Not with the timing. only the bore/stroke spec is different. Because the longer stroke (crankpin further away from center) it will create more torque. Also the longer stroke of the piston will create different pressure changes within the crankcase making a better pump to suck the mixtrure from the carburator and to pump the mixture into the transfer chanels.

I just wonder why super long strokes are better because RPM=horsepower.
A longstroke has the problem of a longer move of the piston so with mass and lubrication limits a longer stroke should run a lower top RPM. That is why F1 engines are running short strokes.

But maybe the 2-stroke concept has influence on the theory of needing more RPM for more HP.