I have been fascinated by Motorized Bicycles since I first saw a Whizzer, some 60+ years ago. I no longer ride as much as I used to, and now use a Sun EZ3 USX recumbent tricycle because I can no longer gracefully get on and off an upright bike. The Sun Trike weighs a lot more than my old PX-10, so I am considering an engine. I have a 13 Hp, electric start Harbor Freight engine with less than 10 hours on it, an Arc Welder, and ideas. 13 Hp seems like a lot, my old Cushman took me all over town with 4 Hp. The 13Hp is paid for, and will have power to spare to run an alternator to charge the battery and make lots of bright lights. The push trailer is where I think I want to go, but I realize I am considering a vast project with half-vast planing. You messages are welcome, I sometimes need a healthy dose of reality.