I have converted several motors, Ryobi 31cc (both rear carb and side carb), Homelites 25cc, and thier 33cc chainsaw motor. I have the homelite 31cc side carb going on a 1/4 scale Sopwith Pup, I just did a 1/4 scale Fokker DVII using a fourstroke weedeater that I converted (34cc), a Bud Nosen 1/4 scale Aeronca Champ, 1/4 scale Fokker DVIII using the Homelite 33cc chainsaw motor and I will have a kitbashed 1/4 scale flybaby using the rear carbed 31cc ryobi engine next spring. Oh, yeah, and a Balsa USA 80inch Eindecker that I used a 25cc featherlight poulan leaf blower motor on.