In most motorcycles all or most of the exhaust system is visible and may be chrome plated as a display feature. Aftermarket exhausts may be made from steel, aluminium, titanium, or carbon fiber.
Motorcycle exhausts come in many varieties depending on the type of engine and its intended use. A twin-cylinder bike may have independent exhaust sections, as seen in the Kawasaki EX250 (also known as the Ninja 250 in the US, or the GPX 250), or a single exhaust section known as a two-into-one (2-1). 4 cylinder machines, super-sport bikes like Kawasaki's ZX series, Honda's CBR series, Yamaha's YZF series, latterly titled R6 and R1, and Suzuki's GSX-R, often have a twin exhaust system. A "full system" may be bought as an aftermarket accessory, also called a 4-2-1 or 4–1, depending on its layout. In the past, these bikes would come as standard with a single exhaust muffler, a practice that lasted until the early 2000s, when EU noise and pollution regulations mostly stopped this practice, forcing companies to use other methods to increase the performance of the motorcycle.