Clean the muffler to remove any dirt or oil that has accumulated on it. This can be done by scrubbing the muffler with paint thinner and a wire brush. Steel wool can also be used.
Sand the muffler with sand paper to further clean its surface and to create a matte finish to which paint will easily stick. Sanding causes the surface of the muffler to roughen so that paint can adhere to it better.
Paint the muffler with paint meant for high-temperature surfaces. Choose a color that best suits the overall theme and style of the motorcycle. Since the muffler will get hot from the running engine, it is important to use a paint that will not melt in high temperatures. On the 6 inches of muffler closest to the engine, apply a heat wrap. The paint can dry with time, or by turning on and off the engine in fifteen-minute increments.
Drill holes in the muffler if a different engine sound is desired. This process can create a louder, deeper muffler sound and it is important to make sure the modification adheres to local noise laws (see Resources). Holes can be added by using a 1/2 inch drill bit on the rear bafflers.
