Originally posted by Dave C
No. But those are just rotary valves versus reciprocating valves.
Yep, 2-cycle technology meets 4-cycle world. The theory is pretty sound, no springs to worry about, no valve float [ever], and a positive seal all the time. The drawback is that the port shapes and sizes are paramount to how well it will perform, if they aren't timed right, you could get pre-ignition and back firing still, which could scorch the valves and wreak havok on sealing ability.