Three wheeler

I'm wanting to put an engine on a Schwinn 26" wheel trike. I'd like to mount it to the rear right above the axle, but I think I could also us a V-frame mount. My main issue right now is installing the rear sprocket on the axle, since there are no spokes to clamp on to. Does anyone have any experience with motorizing three wheelers?

 

[Racie35]

tractor supply sells hubs that bolt to their sprockets for most size shafts....ive used them before and its easy