Replace your Harley exhaust with aftermarket pipes for a more open, unrestricted exhaust.
Two ways are available to get a Harley with a more open, unrestricted exhaust, unless you live in California. The most economical way is to drill a one inch hole through the stock baffles of your Harley. You need a bit at least eight inches long and you must drill in the center of the baffles. Proponents believe this simple solution to the overly restrictive stock exhaust can produce up to seven more horsepower. But, this approach will not work with Harleys sold in California because the catalytic converter gets in the way. Most riders simply replace their exhaust with aftermarket pipes. Here is how you do that.
1. Make sure your engine and exhaust pipes are cool. Cover the frame, engine, swing arm and rear wheel behind your exhaust with clean rags so you will not scratch your paint or chrome. Loosen all nuts and bolts that attach the exhaust system to your motorcycle with a socket wrench or box wrenches.
2. Find the exhaust support bracket behind the exhaust pipes and remove it with a socket and wrench. Spray penetrating oil around each muffler where it joins the exhaust pipe. Wait five minutes and then pull the mufflers off with your hands. Repeat as necessary.
3. Find and loosen the oxygen sensor with a box wrench. Disconnect the oxygen sensor with your hands. Disconnect the head pipes with a socket wrench. Remove and save the retainer rings and clamps from your old pipes for reuse.
4. Bolt on the new mounting bracket included with your replacement exhaust. Always use wrenches to turn bolts. Use a thread locker on the threads. Install the retainer rings and clamps from your old exhaust on your new exhaust with your fingers and a screwdriver.
5. Your new exhaust will probably be a one piece exhaust without slip-on mufflers. Bolt your new exhaust to your exhaust manifold and the new mounting bracket. Hand tighten all bolts and then wrench tighten.
6. Apply Teflon paste to the heat sensor and reconnect. If supplied as separate pieces, insert the new baffle or baffles into the tail pipes. Attach the new heat shields with a flat-head screwdriver.