Volume
Strangely enough, if you want the REAL info on two-stroke operation you need to talk to a MODEL aircraft flyer - particularly one of the pylon racing brigade. What they don't know about porting, pressure patterns and the effect of getting the engine 'on the pipe' with tuned pipe set-ups, isn't worth knowing. It's a bit of a black art and for sheer adrenaline-producing, hair-on-the-back-of-the-neck-raising noise you should hear the sound when a 'piped' 10cc motor 'goes on the pipe'. Awesome!
To return to your original question, from a strictly marginally involved perspective, I understand that it's essentially to do with pressure patterns and their interactions. With properly engineered porting and timing the outputs can be spectacular. As far as I know, the record power output per cc swept volume still rests with a two-stroke - Susuki - if memory serves me correctly....but go find a modeller!!
