I remember Harry ZAK telling me years ago that someone he knew in the bike motor world had spent an inordinate amount of time machining little "blades" or notches in the outside diameter of the crank discs on a crank in some two stroke bike. It made the outside of the crank disc edge look somewhat like a turbine wheel with the "blades" angled somewhat so as the crank rotated in the crankcase it would push more fuel air mixture into the transfer ports, i.e. generating a positive pressure in the crankcase to then pressurize the mixture and force it into the cylinder. Same principle as an internal supercharger. He never said if he found out whether this type modification would serve any useful purpose, but he was not overly impressed with the idea. Whether that was based on some personal experience he or one of the other engine gurus he talked with from time to time that had maybe tried it previously, he did not say and I did not ask.

I was around Harry long enough and had enough personal experience with his motor mods and work he did for me, that with one or two exceptions I knew he knew what he was talking about. Most folks never knew that he was very well thought of in a lot of other racing circles that used two strokes, as well as boat racing, based on motor work he did for other type motorsports that used those type engines.