Wow, I was really impressed by the demo website and breakdown /cutaway pictures!
I remember working in lawncare, mostly with common 5hp +/- Briggs engines, and sometimes a Subaru/Robin 2 cycle 4hp engine. The 2 cycle engine was very smooth and easy starting, had a pleasant sound, and ran on the same mix as the string trimmers. It really lacked torque compared to the briggs, but was great for the run-and-gun-it style of "manicure" mowing I did with some city lawn contractors who mowed all the little patches of grass for businesses to keep the city at bay. I think it would make a sweet motorized bicycle trailer engine.
I have seen youtube videos of go-kart builders turning trash-picked 4stroke 4hp briggs motors into horizontal shaft 2 stroke screamers. They made modifications to the bearings/bushings for oiling, added oil dippers in place of the gear driven oil slingers, and made their own cam lobes, then did some trick welding on the cylinder for the intake. http://www.youtube.com/watch?v=sXScyi4QkYg
Imagine having the "intake" and exhaust both opening simultaneously! Dual exhaust!
Originally Posted by 5-7HEAVEN
Yep, one 6hp Robin engine for $105. I haven't started it yet, but it spins freely now.