Although most people think more cylinders mean more power, some vehicles run most efficiently on smaller engines. A 2-cylinder engine may not pack as much punch as a V8 or V12 engine, but it is more than sufficient for small vehicles, such as motorcycles. Twin engines are popular for sport bikes because they do not add a lot of extra weight. You can find twin engines in straight, V-twin, and flat twin versions. These terms describe the layout of the cylinders, which come lined up side to side in straight twin engines, in a "V" pattern in V-twins, and horizontally in flat twins. Although twin engines are most commonly found in motorcycles and scooters, some other vehicles also use them. Historic cars, such as the Ford Model A, had 2-cylinder engines. Many modern manufacturers, such as Volkswagen and Fiat, experiment with adding twin engines to small, light car models to maximize fuel-efficiency. You can also find twin engines in sport vehicles, such as boats, snowmobiles, and ATVs. Twins come in gas or diesel engines, so it is important to purchase the right kind for your vehicle. Whether you want a new engine for your bike or you want to restore a Ford Model A, you can explore a vast inventory of 2-cylinder engines on eBay.Shop the large inventory of motors, parts, accessories, and complete car and truck engines!