Yasuni is one of the world leaders in the production of high-quality high-end racing exhaust systems for 2-stroke engines. These decades of experience have now led to the only 4-stroke exhaust system, where the system is made of individual segments of pipe. The use of various different diameters and tapers in the chamber allows for optimum gas flow and power output. 10% more engine power and a huge weight saving. Yasuni Scooter 4 exhaust 3.6kg from AISI 304 stainless steel. Silent block mounted bracket with an excellent sound delivered through a specially-designed resonance chamber.