It makes perfect sense to me. First I am an engine guy, so this is something new to explore. A big reason for me is to have something that isn't available. This Decathlon I am putting the honda 4 stroke on is going to be unique. IF fugi or the others later release a 4 stroke then nice, someone can now buy out of the box what I had to build. Money wise, it makes sense too, 0~$60 for a 31cc engine, $60 for the conversion kit delivered to you, and you have a power plant for $60 to $100. Should the weedie put out a little less power, you just up the CC some, if you would use a 27cc factory engine, just use a 31cc weedie. The blocks are often the same between CCs in a similar range.