Emissions were just what started manufacturers to experiment with 4 strokes, there are currently absolutely no bans on selling 2 strokes but yet most of the manufactures have cut back on 2 stroke production, Honda makes no 2 strokes at all now. So why is this? It isn't because of emissions, like I said there is no ban on producing or selling 2 strokes. The reason is simple, the 4 stroke turned out to make a superior race bike, to many peoples surprise. 2 strokes aren't selling now because the consumer is not interested in buying them, it has nothing to do with emissions. So you see there is no problem to be fixed, no the 2 stroke will not make a come back. Sure some of us that have been racing for years miss the sound and smell of a 2 stroke, but none of us racers would trade our thumpers for a 2 stroke. I have owned and raced about 30 bikes over the years, only 2 of them have been 4 strokes, but the 4 strokes are far better race machines than any 2 stroke I've ever owned. I hear a lot of new and inexperienced riders saying that they prefer 2 strokes and the reason is that most of them have never ridden a real 4 stroke race bike. They move from their slow and heavy CRF80 to a 2 stroke 85 and think that 2 strokes are the best thing ever because it is the first real performance bike they have ever owned, but if you put a CRF150R up against that 2 smoke 85 you 'll know why 4 strokes dominate motocross, supercross, arenacross, super moto, GNCC, etc. Don't get me wrong, I still love 2 strokes and enjoy riding them, but I enjoy winning even more so I'll stick with my thumper.