Installing a drz400 full exhaust is pretty much the first thing most people do after they realize how quiet and choked-up the stock bike feels. The Suzuki DRZ400 is a legendary machine—it's basically the "cockroach" of the dual-sport world because it just won't die—but let's be honest, the factory exhaust system is a heavy, restrictive hunk of metal. If you're looking to actually wake the bike up and shed some serious weight, swapping out the entire system from the cylinder head back is the way to go.
Most riders start by looking at slip-ons, but a slip-on only replaces the muffler. On a DRZ, the real bottleneck is often that skinny stock header pipe. By going with a full system, you're opening up the flow, which is exactly what that 398cc thumper needs to breathe properly.
Why the Full System Beats a Slip-on
You might be tempted to save a few bucks and just grab a muffler, but you'll probably regret it later. The stock header on the S and SM models is notoriously narrow. When you bolt on a drz400 full exhaust, you're getting a larger diameter header that allows the exhaust gases to exit with much less backpressure.
It's not just about the power, though. The weight savings are massive. The stock "cannon" that Suzuki puts on these bikes weighs a ton. Most aftermarket full systems are made of high-quality stainless steel or titanium, which can shave five to eight pounds off the bike. On a machine that weighs around 320 pounds soaking wet, losing that much weight high up on the frame makes a noticeable difference in how the bike handles in the dirt.
The Popular Contenders
If you've spent any time on the forums or in Facebook groups, you know there are a few names that always come up. Each one has a slightly different personality, so it depends on what you're looking for.
The Yoshimura RS-2
This is arguably the "gold standard" for the DRZ. Since Yoshimura and Suzuki have a long history of working together, the RS-2 fits like a glove. It provides a great balance of power across the entire rev range. It's loud, but it has a refined, thumpy sound that isn't just raw noise. Plus, it looks great with that signature aluminum or carbon fiber finish.
The MRD Z-Pro
If you want the absolute maximum power and don't care about being the loudest person in your neighborhood, the MRD is the one. These are hand-built, and the craftsmanship is top-notch. The header is even larger than the Yoshimura, which is great for top-end power. One of the best things about MRD is their "you break it, we fix it" warranty, which is almost unheard of in the exhaust world. If you loop your bike on a trail and crush the pipe, they've been known to fix it for the cost of shipping.
FMF Powercore and Q4
FMF is another huge name. The Powercore 4 is a solid, budget-friendly option that delivers plenty of bark. However, if you do a lot of trail riding in areas with strict noise regulations, the Q4 is a lifesaver. It's one of the quietest aftermarket options that still offers a performance bump over stock. It's proof that you don't have to annoy everyone within a five-mile radius just to get a little more throttle response.
Don't Forget the 3x3 Mod
Here's the thing: you can't just install a drz400 full exhaust and expect it to run perfectly right out of the box. In fact, if you don't touch the fueling, your bike will probably run lean, pop like crazy on deceleration, and maybe even run hotter than it should.
To get the actual performance gains you're paying for, you have to do the "3x3 mod." This involves cutting a 3-inch by 3-inch hole in the top of the airbox (hence the name) to let more air in. Since the new exhaust lets more air out, you need to balance the equation.
Once the airbox is opened up, you'll need to re-jet the carburetor. Most guys go with a JD Jetting kit or a Dynojet kit. It sounds intimidating if you've never ripped a carb apart, but there are a million YouTube videos showing you exactly how to do it. When you get the jetting right, the difference in throttle response is night and day. The bike stops feeling "lazy" and starts feeling snappy.
Installation Tips and Tricks
Putting on a new exhaust isn't exactly rocket science, but there are a few things that can trip you up. First, buy a new exhaust gasket. Don't try to reuse the old, crushed copper one that's stuck in the cylinder head. They're cheap, and using a new one ensures you won't have an annoying exhaust leak that makes your bike sound like a lawnmower.
Second, be careful with the header bolts. They've been sitting through heat cycles and getting sprayed with road grime for years. Use some penetrating oil (like WD-40 or PB Blaster) and let it soak in before you try to wrench them off. Snapping a bolt off in the engine block is a quick way to turn a fun afternoon project into a week-long nightmare.
When you're bolting everything up, leave all the connections slightly loose until the whole system is lined up. If you tighten the header bolts all the way first, you might find that the muffler mount doesn't quite line up with the frame. Get everything into place, then tighten from the front to the back.
Noise Levels and Trail Manners
We need to talk about the "loudness" factor. A drz400 full exhaust is significantly louder than stock. While that deep growl sounds awesome when you're ripping through a canyon, it can be a bit much on a six-hour dual-sport ride.
If you plan on doing a lot of forest service roads, make sure your new system has a spark arrestor. Not only is it a legal requirement in many parks, but it also helps take a little bit of the "sharpness" out of the exhaust note. Most systems like the Yoshimura come with a removable insert that lets you tune the sound level to your liking.
Final Thoughts on the Upgrade
Is it worth the money? Absolutely. A drz400 full exhaust is probably the single most impactful modification you can make to this bike. It changes the entire character of the engine. Suddenly, the front wheel wants to come up a little easier in second gear, and the bike doesn't feel like it's struggling to breathe at highway speeds.
Just remember that it's a package deal. If you're going to spend the money on a high-quality full system, budget an extra $80 for a jet kit and a few hours of your time to get the carb dialed in. Once you've got the intake, the fueling, and the exhaust all working together, you'll finally understand why people love the DRZ400 so much despite its "old school" technology. It's just plain fun.