How to replace a motorcycle exhaust

Sport bike Slip-Ons

Before you take the new motorcycle exhaust out of the box, take the instructions out of the box and read them. I know, it’s not macho-esque to read the instructions, but it’s always a good idea, especially with something as expensive as a new motorcycle exhaust system.

For instance, the mounting bracket will be different, it might bolt inside or outside the hanger, there will be different washers, the collector clamp might fit differently than you thought it would.

It sounds tedious and it is, but it’s nowhere near as boring as taking everything apart and doing it again because you rushed into it. The main potential problems are not getting the clamps, etc. bolted up properly. This allows the motorcycle exhaust system gasses to leak (probably around the new joint between the header pipe and the new muffler).

Some slip-on motorcycle exhaust systems offer a high mount option to increase ground clearance. Consult the documentation or ask your dealer if the high mount system retains the passenger foot peg or not. It may be necessary to remove it.

So, now you’ve read the instructions. Make sure you’ve got the right tools, i.e. wrenches, and possibly Allen keys that fit, and get on with it.

Make sure nothing is interfering with the passenger foot pegs or the swing arm. Make sure that the new pipe isn’t going to blow hot gasses at your right rear turn signal or other bodywork.

Once you have those checks done, double check all the fasteners and then fire it up. Some manufacturers recommend re-jetting the carburetor after replacing the stock motorcycle exhaust system. This may or may not involve a dyno run, but it’s a good idea to have it checked.

Cruiser or Sport bike Full Systems

For a full motorcycle exhaust system, things get a bit more complicated, but the same basic method applies. This time however, loosely assemble the full system away from the bike

This is to make sure (a) there are no parts missing, and (b) it all fits together perfectly. If there are any burrs on the joints, now is the time to deburr them with a file and some emery cloth. Don’t wait until later when they’re underneath the bike and you can’t get to them easily.

Take anything off the bike that looks like it might get in the way. That means possibly the fairing, radiator or the oil-cooler. Make sure you know if the center-stand (if there is one) can be retained or not. Make sure you know which header pipe goes to which exhaust port. Assemble loosely at first. If everything is ok, you’re ready to move on.

Gently remove the old exhaust gaskets with a screwdriver or pocketknife. Clean the ports with some contact cleaner and check to make sure the studs and the threads are in good shape. Put a little high-temp grease on the new gaskets to hold them in place, and then loosely bolt the header pipes to the cylinder head.

I recommend always replacing the exhaust gaskets with a new full motorcycle exhaust system. I had problems with leaks on my bike until I replaced the gaskets. A long-term problem with an exhaust leak could cause engine damage.

Some systems have a separate muffler. If so, it’s time to slide the muffler(s) over the header pipes using some more high temp grease. Snug the clamps, etc.

Tighten all the bolts and clamps. Always use a torque wrench where a torque setting is specified. Re-install and refill the radiator and oil-cooler where necessary and start the engine.

Rev it gently because the carburetion might well be upset due to the increased flow. Check carefully for leaks. Get the system hot, let it cool down again and then re-check all joints, clamps and bolts.

Minor leaks usually seal themselves through carbon build-up, but if you can hear anything blowing, go back to step one.

If everything’s ok, replace the bodywork (if necessary), and make sure there are no interference fits. Now you can have a fuelling check on the dyno and marvel at the massive power gains and the nice new sound.

Down the Road

After a few miles it’s always a good idea to re-check all fasteners to make sure nothing has shaken loose. Check for leaks again too.

To care for your new motorcycle exhaust system, keep it clean and dry. If your motorcycle exhaust system is chrome, you might want to check out my article on motorcycle chrome for more tips on keeping it looking good for years. If you ever have damage and need to have your motorcycle exhaust system re-chromed, learn how to choose a chrome plater.

A few parting exhaust notes

• Always read the instructions FIRST.
• Use the correct tool for the job.
• Replace the old motorcycle exhaust gaskets.
• Use a torque wrench on fasteners that have a torque specified by the manufacturer.
• Double check for exhaust gas leaks.
• Go back and check all fasteners after a few miles.
• If required have your carburetion checked on a dyno (if you have access to one).

Now a note from the environmentally friendly side of things:

Be respectful of other citizens. Don’t put an extremely loud set of pipes on your bike and go roaring off through a densely populated neighborhood just to see if you can set off car alarms. As motorcyclists we need to maintain any respect that the “cagers” have for us. I know that may sound “sissy” but I don’t want you messing things up for the rest of us.

I’ll come down off my soapbox now! :-)

I really hope that this article has helped in your quest for information on a motorcycle exhaust system. If you have questions about installing your new pipes, contact us and we’ll do our best to get an answer for you. Also let me know if there is any other information you wish this article had covered.