RE: Supercharger for a 2-stroke
If you use a blower of a size suitable to the engine, you can get a net gain with any piston engine, except a two-stroke with piston controlled ports.
Many of the Detroit Diesel engines are two-stroke, but they have poppet exhaust valves, allowing the exhaust ports to be shut while the inlet ports, piston controlled, are still open. They use the "Jimmy" blowers primarily for scavenging, the way our model 2c engines (and most other 2c engines) use the crankcase's pumping action.
One two stroke that uses a blower with piston controlled ports is the big Faribanks-Morse engine, as used in diesel-electric submarines. But they also have two pistons per cylinder, again, allowing the exhaust ports to close before the inlet ports.
And the "Hot" DDA diesels also have turbos pressurizing the scavenge blower's intake.
So, finally an answer to an earlier question - yes, our model 4c engines can be supercharged to good effect.
And the other question about the YS method - they use the crankcase as a pump, with a rotary valve to control the suction from the carb and the discharge into an air chamber, the big blob you see on the back of most YS engines.
Bill.