How to Insert Baffles for Motorcycle Exhaust Pipes
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Baffles installed in motorcycle exhausts are either welded in or screwed in. Replaceable baffles are secured with a screw or nut and the baffles in solid-piece (can't be disassembled) mufflers are welded in. Some motorcycle exhausts, such as drag pipes, don't have baffles at all.
If the ends of your exhausts are bigger than the middle, you have mufflers. If your pipes are straight you should check the bottom of your exhaust pipes for screws, which indicates replaceable baffles. If you have straight pipes with no screws on the bottom then you can install baffles in your pipes.
Measure the diameter of your exhaust pipe opening with a steel tape. The opening will probably be either 1 3/4 inches or 2 inches across. The baffles you intend to install should be the same size.
Unbolt the right foot peg assembly with an open end wrench and a socket wrench and remove. Remove the heat shields by loosening the large hose clamps that hold them to the exhaust pipes with a screwdriver.
Loosen completely the exhaust manifold flange nuts with a socket wrench and socket. Disconnect the two oxygen sensors on the inside of your exhaust with an open end wrench.
Unbolt both exhaust pipes from the exhaust support bracket with an open end wrench. Remove the exhaust from the motorcycle and separate the front and rear pipes.
Line the jaws of a bench vice with rags. Insert the front exhaust pipe in the vice bottom side up.
Measure the distance from the end of the baffle to the attachment screw hole. Add three inches. Measure that total distance from the open end of your exhaust with a steel tape and mark the end of that distance with a grease pencil.
Drill a 1/4 inch hole in the bottom of your exhaust pipe where you made the grease pencil mark using an electric drill and 1/4 inch bit.
Insert the baffle into the open end of the exhaust pipe so the end of the baffle is three inches from the end of the pipe.
Insert a mechanic's awl into the hole on the bottom of the exhaust pipe. Carefully turn and adjust the baffle until the mechanic's awl catches the screw hole on the bottom of the baffle.
Replace the mechanic's awl with one of the two screws included with your set of two baffles. Apply thread locker to the screw threads and tighten the screw with an Allen wrench.
Repeat the steps necessary to install a baffle in your rear exhaust pipe. Reattach the exhaust pipes to the motorcycle.
- "101 Harley-Davidson Performance Projects"; MBI Publishing Company; 1998
- Harley-Davidson Baffles
- Wrap the pipes with masking tape before drilling to guard against damaging the chrome.
- Matt Cardy/Getty Images News/Getty Images