How to successfully re pack a modern muffler with plastic end cap, (`17 Sherco 125/250/300 example). I removed the rear fender and did not remove the muffler from the bike. There are 3 screws affixing the Sherco cap. It takes some force to work the cap out then work out the core and packing. Everything is in there quite tightly! Here is what puked out: Loud-poppy exhaust will increase over time on any bike with enough hours. That makes a bike sound older than its mechanical age, which sucks. The problem was in the perforated-tube holes becoming clogged and the first turn of fiberglass mat wrap around the tube becoming clogged with hardened oil. The communication between the exhaust tube and the resonance chamber of the final muffler was thus becoming progressively lost. Inspection of the inner or first muffler with a flashlight showed how that part - on my bike anyway - runs hot enough to stay pretty clean. Good news, as that part is not serviceable. I toasted the perforated tube with a torch to burn up the oily carbon. Then I used a dinky screwdriver to force carbon out of every perforation hole. After some wire bushing and re painting the tube looked like new. Here it is just prior to rolling some new insulation and the old mat around it. I found the packing to be quite specialized. The mat is dense and has many tiny spike perforations. The top and bottom chamber packing, in contrast, is much looser, being comprised of a stringy Rasta Man-hair-like fiberglass. The long strings are what tipped me off to the assembly solution of pushing the top and bottom Rasta packing in with a rod AFTER the tube with wrapped mat is assembled back into the muffler body. I used a tie down to bias the tube up to make room to force the bottom packing in, then down to make room to force the top packing in. I was quite happy to be able to re use the original packing. I lit a fire in the mat with my MAPP gas torch (aka propane torch) while holding the mat up to a strong wind. The mat would glow and crackle. I did not let the fire dwell too long so the glass would not melt too much. I'd drop the burning mat on the ground and step on it to douse the fire. I did this multiple times until the critical first-turn-of-wrap was no longer hard like a cold cookie. I found the Rasta hair-packing easier to melt so I only burned the more soaked bottom end of each wad. The mat and Rasta fibers turned white and became a bit more friable after burn-off. To not have the more friable mat fibers blow out of the perforation holes, I cut a thin one turn wrap in fresh standard fiberglass insulation. Though low density, once wrapped under the higher density mat it was mashed tight and flat. Continued in a following post.