How to Drill Out a Motorcycle Exhaust Pipeby Sean Russell
If you are looking for an inexpensive way to create a louder motorcycle exhaust, consider drilling holes in the muffler portion of your slip-on exhaust. Removing stock baffles built into your exhaust will also maximize exhaust sound. Before attempting such a procedure, learn the laws governing exhaust noise in your state. Exhaust noise laws vary by state. Drilling into the main baffle within your slip-on exhaust also decreases exhaust flow restrictions, resulting in engine power gains. Keep in mind that drilling an exhaust system will void an exhaust warranty.
Remove your motorcycle's slip-on exhaust, which includes the muffler. You will be working on the muffler portion of the exhaust. Follow the owner manual or repair manual instructions for locations of the bolts and clamps that hold the exhaust pipe in place. Remove all necessary bolts before attempting to remove the slip-on exhaust.
Cut the exhaust cone out of the tailpipe using a rotary saw tool. Enter from the tailpipe opening of your slip-on exhaust and cut the weld holding the exhaust cone inside the tailpipe. The cone will not be reinstalled, so don't worry about preserving its shape while cutting. Remove the exhaust cone once the cutting is complete.
Shine a light into the bottom of the exhaust slip-on and locate where the exhaust travels from the primary pipe into the second baffle chamber. This will be near the bottom third of your exhaust slip-on at the opposite end of the tailpipe. The main baffle is located a few inches above the second baffle, in the center of the exhaust slip-on. Mark this point.
Mark four drilling points, evenly spaced by quarters around the circumference of the slip-on exhaust at the point of the main baffle chamber.
Drill four holes through the exhaust piping and into the center of the slip-on exhaust using a half-inch drill bit capable of drilling into metal. Make sure each hole is drilled evenly and at the correct point marked in the previous step.
Mark four more drilling points, centered in-between the four holes you just drilled, with a pen. The exhaust markings will now break the circumference of the slip-on into eighths instead of fourths. Make sure each hole is marked on the same circumference line as the four previously drilled holes.
Drill the four new holes using a half-inch drill bit. There will now be eight holes, in line with each other, drilled into the main baffle of your exhaust piping.
Reinstall the newly drilled slip-on exhaust and turn on the motorcycle to hear the sound difference.
Items you will need
- motorcycle image by Dragana Petrovic from Fotolia.com