I have a Saito 100 on mine and I love it. I started with an O. S. 91 and just didn't have enough power. My tank is behind the firewall, and once it is tuned I haven't had any problems. One other guy that I fly with runs his Saito with a pump and the tank on the CG. If I had to do it again I would go with that setup. Will know more about the YS as soon as Wayne gets his in the air