Do You Already have a mounting kit for your bicycle and need to purchase the engine only? We have what you need. The new EPA approved Hua Sheng F142 49cc 4 stroke engine is available in either 78 mm tapered shaft or 5/8" keyed straight shaft. At approximately 2.5 HP this bicycle engine gets about 100 to 150 mpg and can hits speeds of 35 MPH or more. 4 cycle engines require little maintenance. Simply add gas and oil and the engine is ready to operate. Make regular oil changes and your engine will last you for many years to come.