I was looking at this engine just today wishing I could put one on a paramotor…
You would either need a gear reduction or a 600-700cc radial engine to have a decent size prop and even though they are 4 strokes, they still burn oil. Other disadvantages include more maintenance, much higher cost, harder to find parts, and an amazing sound that you just cant resist, so you will be flying a lot. lol.
Radio control radial engines run at a much lower rpm than 2-stroke paramotor engines, so you tend to need a much bigger radial engine for the same power. because of this, I recommend looking into Moki radial engines. You can find them up to 500cc and about 25hp which would be better for most people than the 15hp 260cc engine you have specs pulled up for.
Someday I will make a radial engine powered paramotor with Moki 400cc or 500cc engine and a gear reduction as it would sound amazing and look awesome, but it would be one of those show pieces that you wouldn´t fly often and it would be more for taking to airshows and fly-ins just to blow peoples minds.