MC Garage Video: The Truth About Aftermarket Motorcycle Exhaust Systems

Aftermarket exhausts aren’t the magic bullet they used to be.

An aftermarket exhaust system is at the top of most rider's mod list, but what can you really expect from that fancy pipe, and are stock exhausts all just junk anyway?

A lot of people think the stock pipe on their bike is just cobbled together as an afterthought. Twenty or thirty years ago that might have been the case, and, if you're riding a bottom-dollar bike that may still be the scenario, but for the vast majority of modern bikes, especially sportbikes and performance machines, the exhaust is very carefully engineered. In fact, after the engine, the exhaust system usually soaks up the most R&D resources. That's because it's key to the bike's performance, sound, appearance, and of course compliance with various emissions and noise regulations.

Don’t underestimate that stock exhaust, because every component has been carefully designed to fulfill a specific purpose, and there’s a lot more going on than meets the eye. Most manufacturers pour a ton of effort into designing a good system that provides strong power across the rev range, but stock exhausts are still heavily compromised due to the US and European noise and emissions regulations they must meet. And that is where aftermarket exhausts come in.

Aftermarket pipes are designed for closed course, competition use only. That means such exhaust are not street legal and therefore not restrained by all the rules that stock exhausts must follow. So while your bike’s stock pipe has to check a bunch of noise and emissions boxes, aftermarket exhausts’ only objectives are to cut weight, improve sound, add style, and boost power.

Surprised that I listed power last? It’s last because it isn’t the primary draw these days, or at least it shouldn’t be. Again, twenty years ago you could get big gains simply by slapping on a pipe, but these days, stock exhausts do a damn good job of offering broad, useful power. There is certainly still some room to improve performance, but if you install a full exhaust system, you absolutely have to do it in conjunction with a fuel controller like a Power Commander. If you’re not tuning your fuel to match your new system, you’re leaving power on the table and probably causing your bike to run lean. That means crappy throttle response, high engine temps, and lots of popping on decel.

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In my opinion, the single biggest draw of an aftermarket pipe is weight savings. There’s a lot of crap on stock exhausts, and they’re huge! With no heavy catalytic convertor or massive sound-absorbing bread box or backpressure valve, race pipes can slash pounds off your bike.

There’s also a lot more style and attention to detail in the aftermarket, so swapping to a race pipe can turn your exhaust from an ugly necessity to a point of pride. Welds are more precise, there are nice touches like jacketed springs, polished pipe sections, and of course a trick muffler. Fancy finishes like carbon fiber and titanium are rarely available from the factory, but they’re pretty common on aftermarket systems and some companies really take it to another level.

Aftermarket pipes are louder, too, which some people like. I think race pipes sound obnoxious on the street, and they’re also illegal on account of that whole “competition use only” label. But if you’re still after a little more volume and better tone plus a dose of style, Yoshimura has a whole line of EPA- and CARB-compliant mufflers. And honestly, a slip-on muffler is going to be the best option out there for streetbikes. They’re cheaper, much easier to install, and in most cases won’t require an expensive fuel controller.

So, to summarize, your stock exhaust deserves respect for juggling a lot of difficult jobs, and aftermarket exhausts are good for reducing weight, improving sound and style, and possibly boosting power if you optimize your fueling to match it.