If I were you I'd find a nice garage sale or thrift store steel framed bike and build on that...you'd kick yourself if you found out something simple was wrong with that e-bike...just my 2 cents.
I cant tell for sure because the picture doesnt show that side of the bike, but isnt that a coaster brake? do you pedal backwards to brake? if so, you can still install a chain drive. coaster brakes are common on beach cruisers, and many members here like to put ht kits on cruisers, myself included. its (usually) a simple matter of removing the coaster brake arm, installing the sprocket, and re-attaching the coaster brake arm. some hubs are wider than what the sprocket can fit over, in which case you have two options. make the hole in the sprocket wider, or get a wheel with a smaller hub. you can probably replace that rear wheel if needed with a wheel that has a different type of hub for not too much money. now, fitting a china girl on that frame is going to be a little tricky. there ied to be a website where they sold rack mounts for ht engines, but i can not find it, most likely because i cant remember the exact name of it. perhaps someone else here does.It just occured to me... The hub brake in the back rules out the chain drive idea. So I guess it's friction or fix the electronics on it. Anyone have one to sell? Id like to try used if I can.
i weigh 250 and the bumblebeebolton works great for me!I like to tell people go with whatever you can afford cause in the long run any money spent on a MB is money saved. If you weigh over 200 LBS like I do I doubt that BB is gonna cut it. Hills are hard enough with a 50cc bike. The BB is 26cc and is sold in Florida (it's flatter than Texas there) here's their web site if ya want to read up on them they have testimonials ect. http://bumblebeebolton.com/