This discussion should really be taking place in the tech forum, but I should qualify all that by saying that if the "sole" goal is to reduce emissions to the lowest point possible, whilst maintaining some degree of equivalency with 4 strokes in terms of HP/wt ratios, etc.--I think 2 strokes are doomed. Particularly if the "holy grail" of 2 smoke design is not achieved--a cleaner burning alternative lubricant. Right now, 4 cycle technology is certainly not at its pinnacle, yet their power to weight ratios "as is" are damn near, if not equivalent to current 2 strokes. If one were to apply FI & catalytic converters to current 2 strokes (from data I've seen), less torque/hp certainly would result. That would put them on equal basis with 4 strokes in terms of emissions output, but performance would suck. Since DFI in 4 strokes is only a matter of time, which will in my opinion improve 4 stroke performance as well as emissions, 2 strokes will fall behind another notch.
I really think the only way 2 strokes are going to survive beyond the next 10-20 years (dirtbike applications only) is if the EPA accepts less rigid emissions criteria for 2 smokes &/or a cleaner burning lubricant is designed. On the other hand, they'll obviously persist in chainsaws & such--unless the Wankel motor is brought back.:eek:
Anyway, that's all probably wrong. But oh well, it's just what I see from my seat.