I build HHO systems for home and auto but I've never put one on a motorcycle or moped.
I'd like to make my test subject the Kromag and see if HHO injection to the air intake will have a similar effect as on my element.
The main issue would be heat. I had to expand my element's air intake and ad heat sinks to keep the temperature down. In pre-obd vehicles the added heat doesnt cause much of a problem as long as the air intake is clean and the HHO flow is well regulated.
On a two stroke moped, its going to increase the heat significantly.
Since it is a moped there would also be a lot of movement in the tanks.
First idea is to make a flow-through HHO reaction tank with copper tube instead of plates or wire and let it drip off the reacting water as a feeder tank drips in fresh water. Also attach heat sinks to the reaction tank.
This will keep the tank temperature down.
The power would have to come from a charged 12v battery with a PWM.
For pressure I was thinking of making a gravity compressor with blowbacks on both sides.
I Figure that the oil mix should be increased a bit. If a moped can work on HHO without drying out or over heating, maybe it could run with just hydrogen and an oil drip from the gas line.