In a new program at the nonprofit Community Bicycle Center in Biddeford, teenagers learn how to recondition bikes and run a business. Currently, there are five teens in the Kids Bike Factory, which started in March. Each week they attend a class where they learn about everything from marketing to inventory management and customer service. They put their business skills to work selling bikes online and at local events. They’re paid a small monthly stipend. Profits from the sales go back into the program. The factory will have 50 bicycles for sale this Sunday at the Great Maine Bike Swap at the Sullivan Recreation and Fitness Center at the University of Southern Maine in Portland.