A quiet motorcycle muffler starts with the kind of engine that the motorcycle has. The quietest engines are small with a high number of pistons. You can quiet most of the noise that a motorcycle makes by switching out a large, low-piston engine for a smaller engine. However, if you do not want to switch out the engine or you simple want to make your current engine quieter, you can pack the muffler to reduce most of the engine noise.
Remove the muffler from the motorcycle exhaust system using the socket wrench. The muffler is the part of the exhaust system that sticks out from the rear of the motorcycle. It should have a small cap on the end covering the hole. If the muffler is held in place by rivets instead of bolts, then use a drill to carefully drill the rivet off of the brackets holding the muffler in place.
Clean the exterior of the muffler after you have removed it from the motorcycle with a soft cloth and degreasing cleanser. This will make it easier to pack the muffler because your hands will stay clean and you will be able to see what you are working on.
Drill through the rivet holding the muffler cap in place. Use a rubber mallet to gently tap the cover to release it from the muffler.
Put on thick work gloves. Remove the current muffler mat from inside the muffler. Unwrap the old mat from the core and set it aside. The matting inside the muffler is what muffles most of the sound from the engine. Over time, the matting becomes flattened. When the matting is flat, it cannot absorb the sound as well. Replacing the matting will create a better sound barrier.
Place the old muffler mat over the new fibreglass matting. Cut out the new mat to equal the size of the original mat.
Roll the new mat around the core. The core also helps in sound absorption, but it does not flatten like the matting, so it does not need replacement unless it is broken. Hold the mat tightly in place around the core. If you do not wrap the core tightly enough, it will not fit inside the muffler. Tape the mat in place around itself to hold the roll.
Stuff the core inside the muffler. Trim any excess matting that sticks out from the core with scissors.
Replace the muffler cap and line up the rivet holes. Place a rivet inside the rivet gun tip. Line the tip of the rivet gun with the holes in the muffler. Press the rivet trigger to install the rivet inside the holes. The rivet gun closes the end of the rivet, making it so that the rivet cannot fall out of the hole.
Slide the end of the muffler into the exposed portion of the exhaust system. Screw the muffler brackets back in place around the muffler, holding the muffler in place. If necessary, install a rivet between the exhaust piping and the muffler for greater stability. However, only install a rivet if there are already rivet holes on both the exhaust pipe and the muffler. The engine sounds will now be greatly reduced.