A cafe racer air filter is a type of air filter specifically designed for cafe racer motorcycles. Cafe racers are a style of motorcycle that appeared in the 1960s, characterized by a clean, minimalist design and high-performance engines. Cafe racer air filters are generally high flow, washable and reusable, and are designed to increase horsepower and improve engine performance. Some popular brands of air filters for cafe racers include K&N and BMC.