Matt,
That breaking is the key of success in pattern. Clearly YS when to the process and decided that 4 cycle was the best solution for pattern. That is been proven tecnology. The new OS 4 cycle clearly is not designed for pattern. If someone wants to be serious about developing a gasoline engine for pattern for sure they should consider a 4 cycle with the features the YS 175 already have. Just cut and paste it. I am not expert in engines so probably it is impossible to do it with gasoline engines.