Haynes V-Twin Motorcycle Engine Kit: What is it? It\'s a scale model of a V-Twin, 4-stroke motorcycle engine that works! And, with its clear casing, you can see how all the parts move inside it. Plus, it has an electronic engine sound and light-up spark plugs. About the product This build-it-yourself kit has everything you need to construct the engine, including all the parts, screws, and a screwdriver. Oh, and detailed, step-by-step instructions with diagrams. How is it powered? There\'s no actual petrol involved. This engine runs entirely off 3 AA batteries, which aren\'t included. Why you should buy it It\'s a super-fun project that teaches you how internal combustion engines work. It\'s great STEM learning and is sure to have petrol heads (battery heads, maybe?) all revved up! | Haynes V-Twin Motorcycle Engine Construction Kit