Repairing a motorcycle muffler can be a lot easier and cheaper than replacing it. Also, if the repair is minor, why go to the trouble of putting on an entire new muffler? With the right equipment, repairing a motorcycle muffler is quite easy.
Make sure you have three pairs of vise grips since you’ll need them all to carry out the task. One will be for the silencer end of the exhaust and the other two will be for the header end. Vise grips are the easiest way to seal the exhaust.
Buy automotive style block plugs. They should be the same diameter as your exhaust pipe. However, you can buy ones that are a bit larger and reduce their size accordingly. Do this by burning the outer edge then wiping off the layers with an old towel until they’re an exact fit.
When you put the plugs in, they should extend out of the motorcycle muffler just far enough to allow you to attach the vise grips to the end of the pipe. This lets the vise grips act as stoppers so the plugs won’t blow out. The vise grips have to be attached at 180 degrees to each other and fiited very tightly. The single vise grip at the silencer end can be attached to the pipe at any angle.
For a heat source, employ a set up that uses oxygen and acetylene or a MAPP gas hand-held cylinder. Have a tip attachment fitted to it. The beauty of these is that these cylinders are readily available at most hardware stores, are quite cheap and last a long time. On the downside, they can take quite a while to heat a dented area.
You can also use an oxygen cylinder and a MAPP gas cylinder as a dual system. This gives more heat although they don’t last anywhere near as long.
Don’t heat your exhaust until it’s been pressurized to between 80 and 120 psi by an air compressor. Feed the tube from the compressor in through the header end. The metal needs to be heated until it’s glowing red but take care not to melt it. If you go slowly, it will be much easier. Keep the heated area pointed away from you at all times.
Once the area to be repaired is glowing red, use a finishing hammer and tap in a circlular motion around the area of the motorcycle muffler that has to be repaired. This will usually remove most of the dents to the point where you can’t see them. If you’re working on a seam, you will have to work slowly to prevent it from splitting.
If you have a nickel/chrome pipe, you might have some discoloration following the repair of the motorcycle muffler. Using a wire wheel on a drill will help to remove this. You can polish the chrome afterwards. Be sure to use a good quality chrome polish on a soft wire wheel and follow up with plenty of buffing using an old, dry towel. After this, your motorcycle muffler will look as good as new.