How to Rebuild a Non-Rebuildable Muffler, Spark Arrestor
Later on, I ran it on the dirt and found that there was a flat spot in the power band from about 4500 RPM on up. I checked the jetting and it was okay, and the sparkplug was more or less in the ballpark. After checking all the usual suspect areas, such as the air filter and worn-out reed valves, I turned my attention to the muffler.
And there was the problem. My first clue was a whole bunch of black mung and drool coming out the end of the muffler. I inserted a wooden rod down into the muffler and rotated it around a few times. It came out coated with black grunge.
The muffler itself was of the non-rebuildable type, meaning that it was put together with pop rivets and not designed to come apart for cleaning or packing replacement. This didn't slow me down a bit. With the aid of a handy drill, I was able to make rather short work of the aluminum rivets. Once the rivets were apart, I was able to lightly tap on the muffler with a rubber hammer and take it completely apart.
While most of the muffler came apart OK, the spark arrestor insert itself was very stubborn to remove. By using a long extension and a hammer, I was able to gently tap on the insert and eventually to free up. When I removed it, the reason for the hesitation in the power became more than apparent. The spark arrestor insert was completely clogged up, and it's amazing that the bike was able to run at all.
When I decided to rebuild this muffler, I didn't really need the spark arrestor insert here in Arizona. To set a fire in the desert, you'd have to be some sort of miracle worker and I figured that simply rebuilding and re-packing the muffler would be the answer. So follow along as we go through the process.