Upgrading your stock grom exhaust pipe is basically a rite of passage for any Honda Grom owner who wants to get more out of their ride. Let's be real: the factory exhaust that comes with the bike is a bit of a letdown. It's heavy, it's bulky, and it makes the bike sound more like a quiet sewing machine than a proper motorcycle. If you're looking to add some personality to your bike, a new pipe is usually the very first place to start.
It doesn't matter if you have a first-gen OG, an SF, or the newest five-speed model; the philosophy remains the same. You want something that lets the engine breathe, sheds some unnecessary pounds, and makes people actually notice you're coming down the street. But before you just buy the first shiny thing you see on the internet, there are a few things worth talking about.
Why People Swap Out the Factory Pipe
The most obvious reason to ditch the stock setup is the sound. The Grom is a 125cc single-cylinder engine, and in its stock form, it's muffled to the point of being nearly silent. While that might be great for sneaking out of your neighborhood at 6 AM, it's not exactly thrilling. A high-quality grom exhaust pipe gives the bike a much deeper, throatier "thump" that matches the fun-loving nature of the bike.
Then there's the weight factor. If you haven't taken your stock exhaust off yet, you're in for a surprise. That thing is surprisingly heavy for such a small bike. Most aftermarket systems are made from stainless steel, aluminum, or even carbon fiber, which can cut the weight of the exhaust system in half. On a bike that only weighs about 230 pounds, losing five or six pounds is actually a noticeable difference in how the bike flickers through corners.
Finally, there's the look. The stock pipe is functional, but it's not exactly a work of art. Whether you want a high-mount pipe that sits right under the tail or a low-mount system that keeps the center of gravity down near the asphalt, the aesthetic upgrade is a huge part of the appeal.
Full System vs. Slip-On
When you start shopping, you'll notice two main categories: full systems and slip-ons. For most bigger bikes, a slip-on is a common "budget" choice, but for the Grom, almost everyone goes for the full system.
The Slip-On Approach
A slip-on replaces just the muffler part of the exhaust. It's cheaper and easier to install, but on a Grom, the performance gains are basically zero. You might get a slightly better sound, but because the header pipe on the stock Grom is so restrictive, you're still hitting a bottleneck. Honestly, most people regret getting a slip-on and end up buying a full system six months later.
Going for the Full System
A full system replaces everything from the engine head all the way back to the tip. This is where you actually see a change in how the bike runs. By opening up the flow with a wider header pipe, you allow the engine to move air more efficiently. You aren't going to turn your Grom into a 600cc sportbike, but you'll definitely feel a bit more "pep" in the mid-range and top end. Plus, it just looks much cleaner without that bulky stock header.
High Mount vs. Low Mount Styles
This is a hot topic in the Grom community, and it really comes down to what you plan to do with the bike.
High-mount pipes are the classic Grom look. They tuck up under the seat or high along the side. They're great if you're worried about ground clearance or if you just like that "scrambler" or traditional mini-bike vibe. One thing to keep in mind, though, is heat. If you carry a passenger or have soft luggage, a high-mount pipe can get pretty toasty.
Low-mount pipes exit down by the rear wheel. These are popular for a few reasons. First, they lower the center of gravity, which theoretically helps with handling (though on a Grom, it's mostly for style). Second, they stay out of the way of your legs and gear. Stunt riders often prefer low-mount setups because they don't get in the way when they're throwing legs over the seat or standing on the subframe.
Material Choices and Durability
What your grom exhaust pipe is made of matters for both longevity and how much it'll burn your wallet.
- Stainless Steel: This is the gold standard for most riders. It's durable, handles heat well, and won't rust out after one rainy ride. It's a bit heavier than titanium, but it's much more affordable.
- Carbon Fiber: These look incredible and stay cooler to the touch than metal pipes. However, carbon fiber can be a bit more fragile over time, especially if the internal packing wears out and the heat starts to bake the resin.
- Titanium: This is the high-end stuff. It's incredibly light and develops a beautiful blue/purple tint after a few heat cycles. It's also the most expensive option. Unless you're building a show bike or a dedicated race Grom, it might be overkill, but man, does it look cool.
Does It Actually Make the Bike Faster?
Let's be honest for a second. We're talking about a bike that makes about 9 or 10 horsepower. Adding a new grom exhaust pipe isn't going to suddenly make you win drag races against real motorcycles. However, a good exhaust paired with a high-flow air intake can give you a noticeable bump—maybe 1 to 1.5 horsepower.
That doesn't sound like much, but on a Grom, that's a 10% increase. You'll notice it most when you're trying to maintain speed on a slight hill or when you're tucked in trying to hit that elusive 65 mph on the flat. To really see the benefits, you'll eventually want to look into an ECU flash or a fuel controller, as the bike tends to run a bit lean once you open up the exhaust.
Installation Tips for the DIY Mechanic
Installing a new pipe is one of the easiest jobs you can do on this bike. You don't need a professional shop; a basic set of sockets and some patience will get it done in under an hour.
A pro tip: always buy a new exhaust gasket. They're only a few bucks, and using the old, crushed one is a recipe for an exhaust leak. Also, be careful with the studs on the engine head. You don't need to crank them down with all your might—just get them snug. If you snap a stud off in the engine head, your "fun afternoon project" just turned into a nightmare.
Once the new pipe is on, wipe it down with some rubbing alcohol before you start the bike. If you leave oily fingerprints on the metal, they can actually "bake" into the finish once the pipe gets hot, leaving permanent marks.
Living with a Louder Bike
Before you commit to the loudest pipe on the market, think about your daily ride. A short, "straight-pipe" style exhaust might sound cool for five minutes, but if you're commuting for 30 minutes at full throttle, that constant droning can get old fast.
Many high-quality systems come with a removable "DB killer" or baffle. This is a life-saver. It lets you tone it down for the daily grind but gives you the option to let it rip when you're out at a weekend meet with friends. Your neighbors will probably appreciate it, too.
The Bottom Line
Upgrading your grom exhaust pipe is easily the best bang-for-your-buck modification you can do. It changes the entire character of the bike, making it feel less like a toy and more like a proper machine. Whether you're going for a premium brand name or a more budget-friendly option, the sound and weight savings alone make it worth the effort. Just pick a style that fits your riding goals, grab a fresh gasket, and get to wrenching. Your Grom will thank you for it the next time you twist the throttle.