Re: Hello from Arizona! Planning 2 builds.
Look into the horizontal Honda clones; they come in 50, 70, 110, & 125cc and are 4 cycles. They can be had in full auto, semi auto (shift, but no clutch) and full manual shift. Even some come with full wiring harnesses for lights, directional signals, and accessories (cell phone chargers, etc.; your imagination is the limit). They've got the power to do what you want. I think they look more substantial than a 2 cycle engine. Home Depot has the Honda GX120, 160, and 200 clones by Lifan Power USA, I even saw and electric start version! With 4 to 6.5hp, I bet any of those would do right by you too!