(or spark arrestor as Suzuki calls it) exits the exhaust system at the end of the external shell. At the front of each pipe was a small forward-facing grille which allowed cool ambient air to be forced into the pipe by the bike's forward motion and to travel the length of the exhaust between the internal and external pipes. It then flowed through the holes drilled in the stinger, mixing with the hot exhaust gasses before exiting the system. Even so, Suzuki found it prudent to fit heat shields on the outside of the pipe to further protect riders and pillions. The bike's sound is unique among its two- and four-stroke contemporaries but also quite loud. Early in production (December 1974, Frame #11901), Suzuki reduced the size of the spark arrestor tubes, which both reduced noise and horsepower, but the RE5 exhaust note remains distinctive. See also List of motorcycles by type of engine References Citations Sources 'Suzuki Production Rotary Engine, Model RE-5 for Powering Motorcycles'; SAE paper 770190 External links Motorcycle Hall of Fame Museum: 1976 Suzuki RE5 Rotary RE5 Motorcycles powered by Wankel engines Motorcycles introduced in 1974