hey alec, welcome. there are many different options for motorized bicycles, including kit and non-kit engines. figuring out which option will work best for you depends on what range of performance you are looking for and how much money you are willing to spend. some enthusiasts have managed to get more performance and reliability out of inexpensive setups, while others choose to spend a little extra to get more bang for their buck. still others are happy with the stock performance of a kit supplied engine. so do some exploring and look around the site, and you can find a lot of information on different types of setups.