This thread highly divergefied, and I apologize for helping hijack it.
What I've been saying all along is that we can make clean running 2 strokes. Flying horse is already doing this.
I worked in the scooter repair business, and that image I posted earlier of the Adly Thunderjet 50, well that bike came with a catalyst, just like the ones on automobiles, but smaller and all it needs to work is the exhaust heat and fumes from a 2 cycle engine. Some scooter makers add their own air source upstream of the cat, fed by a one way valve that works on the venturi principle to a nipple in the header tube to make the catalyst light off sooner.
It's a proven tech, Tanaka and Husky weedeaters are using the same clean burn technology, in many ways you can more easily make a two stroke burn clean than you can a 4 stroke small engine.
So these concerns about 2 strokes being too old school because of pollutants are not valid any more, in fact I'd expect that the recent run of unitized head/cylinder bike engine kits will start coming with working catalysts soon.
I should post a video of my Husky weedie as it warms up under load. You can see the smoke from the engine slowly start going away as the cat heats up and starts burning off the residual gasoline and oil. It's a game changer and it's been here since 2006.