Standard Chrome 4-Stroke Muffler Exhaust The Standard Chrome 4-Stroke Muffler fits up to the exhaust port for the 49cc 4-stroke Flying Horse 5G and Huasheng 142F bike engine kits Installation requires moderate experience: first remove the exhaust cover from the motor. Then remove the existing mounting studs and replace them with shorter studs. Then install the muffler and clamp it to the motor, and you're ready to ride Note: You will need an exhaust gasket and shorter studs before installing, as they do not come stock with most 4-stroke motors