The Kawasaki Ninja 650R, also called ER-6f or EХ-6, is a motorcycle in the Ninja series from the Japanese manufacturer Kawasaki sold since 2006. The 2012 model drops the R suffix from its name. It is a middleweight, parallel-twin engined motorcycle, designed for normal use on paved roads. They have modern styling and features, with low-seating ergonomics and a low center of gravity. The engine has a 180° crankshaft, resulting in an uneven firing interval of 0° and 540°.