I have the same bike.
The real problem is, two strokes can be made as clean as a 4 stroke.
They have developed direct injection for two strokes which greatly reduces their emissions AND saves fuel (of course).
I went to CSU's small engine lab for a tour, when they put them on the small two strokes in the developing world the fuel savings in the first year pay for the conversion.
Why doesn't Japan incorporated devlope this for us? Who knows.
A few reasons:
1. it's PC to be green and keeps them in better grace with the politicians.
2, They love to sell parts, and 4 stroke dirt bikes eat parts in mass quantities when raced.
3. until recently the hardware needed to fuel inject a dirt bike, in dirt bike operating conditions was not cost effective. (Now that it's available... see number 1)
