In this category you'll find all the complete mufflers we can get for your 4-stroke GAS GAS like the MCF, ECF,... We offer mufflers from ART, YOSHIMURA, PRO CIRCUIT, CRD, SCORPION,... These exhaust lines include the manifold as well as its silencer. A muffler is less important on a 4-stroke engine than on a 2-stroke. But they are often not perfectly designed on original machines. A complete exhaust system saves weight and performance on your engine. Often easy to install, giving your motocross bike a racing look.