<blockquote>In this aspect, my friction drive,rack mounted 31cc Honda 4 stroke GX30 engine was easier to live with day to day than the average frame mounted left side drive china doll (if not a bit boring performance wise and ungainly in appearance).</blockquote>
I recently switched out my china 2-stroke for a Honda 50cc on friction drive.
I'm happy with this decision. It's quieter, smoother, more fuel efficient, and doesn't smell as bad. I still like the 2-stroke though. I want to get another bike and put it on that.
The differences as I see it (not a mechanic type)
+ More powerful. 200% more power strokes per rpm.
At higher RPM it's not that big of a difference though.
- likes gasoline a lot
- top end wears out faster
- sustained travel at (relatively high) speed wears it out faster
- must carry around 2-stroke oil. Unless you have oiling system (none of these kits seem to have that) then you need to premix gasoline in separate container (ideally)
- lower torque. Especially off the line
- more complex. You have the valve train.
- typically more expensive
+ typically more efficient
+ less exhaust stink
+ longer times between overhauls
+ better at long distance at sustained speed
+ get gasoline at any gas station.
And it seems that 2-strokes are much more finicky with changes and fuel mixture. Like they will tend to foul plugs much easier then 4-strokes if they get out of tune. More sensitive to temperature changes (and other environmental factors) and jetting needs to be mucked around with a lot more. Although this could just because I have far less experience with small 4-strokes then 2-strokes. But I won't drive anywhere on a two stroke without having a extra spark plug in my bike's tool kit.
If you want something that is cheap, fast and good for jack rabbit starts. Fun and fast... then 2-stroke is where it at.
If you want something that will be traveling longer distances at sustained speeds then 4-stroke is what you want. Much more neighbor friendly also.