hi i am new here and just started a project for my boys, i was givin three ryan idc trimmers 284 models and two run, i am building a gas scooter now and have found that these trimmer engines are used for a lot of applications, the trimmers i have dont have any marking as to what cc the engines are so i took the piston from one and measured it across the top at 35 mm and the same on the stroke, can some one help me determine the cc, i think that it might be in the mid 30's but am not sure, thanks jeff

Jeff, Jump over to the Giant Engines forum. There is a lot of info and people that can help you there.
Brian