Thinking about starting a side business

Hello everyone, I am somewhat new to this hobby and I am having a blast. I really enjoy riding the bike I built but I think I had even more fun building it. I am thinking about starting a side business with a friend who works in a bike shop. We plan to build and sell complete motorized bikes. We are looking into building the 66cc 2 stroke kit with a cruiser bike. I was wanting to see what you guys have to say about it. Anyone here attempted it aleready? Was it a success and if it was what made you successful? What are some problems or setbacks you have had. Also I have been doing research on which kit to buy. I want to get one that is good so that I can sell a product I am confident in but I also want to get it at the best price possible. That goes for the bike too. Any type of response is welcome here I am just looking for ideas. By the way here are some prelimenary ideas we have had so far. We plan to market our product on craigslist as well as taking the bikes to car shows on the weedend. We have even thought about selling a complete bike on ebay. Another question I just thought of is, what do you think a fair price is for a complete bike? We are going to be maticulous with the build and add parts from sick bike parts like a new tank seal, engine hardware kit, plug, wire, etc. to make it as reliable as possible. We are also going to service the bikes for a shop charge if people need repairs. Thank you in advance for your ideas.