How to Rebuild a Motorcycle Muffler
Most stock motorcycle mufflers are built around a series of chambers and valves to reduce noise and emissions. This often prevents a stock muffler from being rebuilt, because it loses its ability to muffle the exhaust. However, many aftermarket mufflers are built around a removable core that is wrapped in a fiberglass sound-reducing material called packing. The packing burns off during normal operation, and the sound level of the exhaust will increase. Replacing the packing will lower the exhaust volume.
Other People Are Reading
Things You'll Need
- Screwdriver
- Socket wrench and sockets
- Drill
- 1/8-inch drill bit
- Metal punch
- Hammer
- Rubber mallet
- Heavy-duty work gloves
- Fiberglass packing material
- High-temperature silicone sealant
- Shop towel
- Rivet gun
- Stainless steel rivets
Instructions
-
-
1
Turn off the motorcycle and allow the muffler to cool. Loosen the clamp attaching the muffler to the motorcycle's exhaust pipe, using a screwdriver. Unscrew the muffler hanger bolt, usually located at the top of the muffler body or attached to a hanger strap, using a socket wrench. Pull the muffler off the exhaust pipe, using a slight side-to-side motion.
-
2
Drill out the center of the rivet attaching the muffler's inlet and outlet caps to the muffler body, using a 1/8-inch drill bit. Dislodge the outer portion of the rivets from the muffler body with a metal punch and a hammer.
-
-
3
Pull the outlet and inlet caps from the muffler body. Tap the cap lightly with a rubber mallet, if needed, to free either cap from the muffler body. Set the outlet and inlet caps aside.
-
4
Put on heavy-duty work gloves, then reach into the muffler body. Grasp the inner core and the old packing material, then pull the core and packing material out of the muffler body. Shake out any remaining packing or debris from the muffler body, then set the muffler body aside.
-
5
Lay the inner core on a work surface and unroll it from the old packing. Discard the packing.
-
6
Lay a new sheet of packing material onto your work area. Place the inner core along the edge of the packing, then roll the packing snugly around the core.
-
7
Slip the freshly wrapped inner core into the muffler body.
-
8
Coat the mating surfaces at the bottoms of the outlet and inlet caps with a thin bead of high-temperature silicone sealant. Push the outlet and inlet caps over the ends of the inner core and into the muffler body. Tap the outlet and inlet caps with a rubber mallet, if needed, to seat the caps into the muffler. Wipe off any silicone sealant seeping out from between the muffler body and outlet or inlet caps, using a shop towel.
-
9
Secure the outlet and inlet caps to the muffler body, using a rivet gun and 3/8-inch stainless steel rivets.
-
10
Slip the muffler onto the motorcycle's exhaust pipe. Screw the muffler hanger bolt into place, using a socket wrench. Tighten the muffler's clamp, using a screwdriver.
-
1
Tips & Warnings
When replacing the packing material, do not roll the new packing too tightly around the inner core because exhaust gases must be able to pass through the packing layers.
