Kawasaki KLX300R Exhaust (Pro Circuit, FMF, Yoshimura) – Which One is the Best?

Are you interested in a new Kawasaki KLX300R exhaust system? If so, you’re in the right place. As it turns out, I’m a bit of an “over-researcher” and I’ve compiled my list of what I consider to be the best KLX 300R exhaust pipes, slip-ons, mufflers, etc.

There are a handful of decent options out there, but if you really want the best exhaust system for your KLX, I recommend sticking with one of the top, well-known brands.

Here is a list of the different brands that I would choose from:

• Yoshimura
• Pro-Circuit
• FMF
• White Brothers
• Big Gun

We’ll get into the details of these, and the “others” as we go, but in the end, it does matter which exhaust you go with.

There are some exhausts that offer low-end and midrange gains, while there are others that focus on top-end power. No exhaust system does it ALL, but there are some that come close. Either way, you must decide what is most important to you so that you can choose the right exhaust.

For instance, when it comes to getting an aftermarket exhaust for your KLX300R, what are you looking for?

• More all-around power?
• Faster top-end speed?
• Increased low-end torque?
• Overall better throttle response?
• Louder, throaty sound?

Any one of the following aftermarket KLX300R exhausts will improve some aspects of performance, but they just might focus more on the top-end or bottom-end power.

With all of that in mind, the following are the top KLX300R exhausts. There are options to choose from based on the best performance exhaust, the loudest, the quietest, and good cheap exhaust.

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Pro Circuit T6 Exhaust System

Although Pro Circuit exhausts may not always be my top choice, they are for the KLX300R. Pro-Circuit makes one of the best KLX300R exhaust systems you can buy.

With this aftermarket exhaust, your Kawasaki should sound better, look better, and perform better than with a standard exhaust system. The PC T-6 exhaust is made from stainless steel and brushed aluminum and finished off with a carbon fiber end cap on the muffler.

The bottom line, Pro-Circuit produces great exhausts for the KLX300R and for just about any other dirt bike. In fact, the KLX140 Pro Circuit exhaust is one of the best as well.

I have personally run a Pro Circuit pipe on one of my dirt bikes and I really liked it.

Features & Highlights

• Improved performance throughout RPM range
• Aluminum canister
• Has RC-4 resonance chamber
• Carbon fiber end-cap
• Stainless steel head pipe, mid pipe, and end-cap
• Removable USFS spark arrestor
• Lightweight

Positive Reviews

• Sounds good (deep tone)
• Great quality and finish
• Easy to install
• More airflow
• Great fit
• Better throttle response

Negative Reviews

• Not cheap
• It is a little loud without the insert

The Pro Circuit KLX330R exhaust is definitely one of the best options available. They are built well, look good, and sound good. What’s not to like?

Click here to view pricing and read reviews on ProCircuit.com.

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FMF Powercore 4 Exhaust (Slip-On)

Whenever people are talking about exhaust systems and/or pipes, FMF always comes up in the conversation. Not only is FMF synonymous with aftermarket exhausts, but they are also well-known for being some of the best.

There’s no denying that FMF is one of the more popular brands for many weekend warriors and professional racers alike. They make a great product for an affordable price.

If you’re looking for the best bang for your buck, the FMF Powercore 4 slip-on is an excellent option. These are probably the best exhaust for the money, and certainly one of the most popular. I do still recommend buying a 4-stroke exhaust plug for your dirt bike, as these keep water and grime out.

Features & Highlights

• Removable spark arrestor
• Made with stainless steel and aluminum
• Lightweight
• Increased airflow (more power)
• Increase in power and torque throughout

Positive Reviews

• Affordable
• Sounds really good!
• Noticeable performance increase in the low and mid-range
• Overall improved throttle response
• Better acceleration
• Built good
• Easy to install

Negative Reviews

• Not a big increase in horsepower
• It does not include a new head pipe

If you aren’t ready to fork over your hard-earned Satoshis on a full exhaust system, the FMF slip-ons are a great, almost cheap exhaust for KLX300Rs. These provide improved low-end and mid-range power, and they look and sound good.

Click here to view pricing and read reviews on fmfracing.com.

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Yoshimura RS2 Exhaust (Slip-on)

Yoshimura seems to always be in the running when it comes to picking an exhaust. And when it comes to choosing the best exhaust for KLX300R dirt bikes, Yoshi is right there again near the top.

This KLX300R Yoshimura exhaust is a slip-on…. comes from the original Yoshi TRC exhaust, and it is engineered to provide more power, better power delivery, and a super crisp throttle response. Oh, and did I mention that Yoshi sound!?

Overall, this Yoshimura exhaust is one of the better aftermarket options out there. Yoshi makes one of the best-sounding pipes on the market, and they provide improved throttle response, slightly more power, and they weigh less than stock.

Features & Highlights

• Uniquely shaped sleeve (looks and sounds cool)
• Large core and increased muffler packing volume (makes it quieter)
• Stainless steel cone end-cap
• Stainless steel header and tail-pipe
• Spark arrester included (USFS Approved)
• Improved horsepower and torque throughout the entire powerband

Positive Reviews

• Improved low-end
• Improved top-end
• Built great
• Looks awesome
• Weighs less than stock
• Not too loud
• Great throttle response
• Easy to install
• Great for stock 300 KLX
• Best sounding exhaust

Negative Reviews

• Expensive
• Hard to find in stock

Even though picking the best KLX 300R exhaust can be subjective, I think most would agree that these belong in the conversation. Not only do they make more horsepower and torque, but they also look and sound great, all while improving throttle response. Its no surprise that the manufacturer of the best KLX110L exhaust also makes an option for the 300cc.

Click here to view pricing and read reviews on Amazon.

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Other KLX300R Exhausts

Unfortunately, there aren’t as many aftermarket exhaust systems for this dirt bike as there are for some of the minis or motocross bikes. However, there are a few other companies that make decent options.

Here are a few of the “other” exhausts that you could look into, although they aren’t quite as recognizable as the big dogs are.

• White Brothers Exhaust
  • No spark arrestor, very loud, hard to find
    
• Big Bun EVO Exhaust
  • A removable “screen-type” spark arrestor, Not legal in CA

KLX300R Jetting for Aftermarket Exhaust

It’s wise to check and/or adjust the KLX300R jetting after installing an aftermarket exhaust.

It’s not uncommon to re-jet your dirtbike after upgrading your exhaust or to adjust with an electronic jet kit. Oftentimes, you’ll need to adjust your bike so that it runs a little richer after adding a new pipe.

1997-2007 models: Click here to view pricing and read reviews of the KLX300R Carburetor Jet Kit on Dynojet.

2020-2023 models: Click here to view pricing and read reviews of the EJK on electronicjetkit.com.

Should you change jetting on your KLX300R?

If your Kawasaki 300R is running too lean after upgrading the exhaust (it likely is), you will want to adjust the jetting one setting richer at a time and then test. It’s important to test after every adjustment until the bike reaches its peak performance.

Here’s what your bike will do if you need to rejet:

• Spark plug fouling often
• Sputters easily
• Bogs down
• High idle
• Poor throttle response
• Easily overheats
• Hard to start
• Loss of power

Is your jetting too lean?

Again, if you add an aftermarket exhaust, it’s likely that your Kawasaki KLX 300R is running lean. Here’s what you should notice from a bike that is running too lean:

• Hard to start (when cold)
• Cuts out/bogs down when trying to “snap” throttle
• Idles high

Is your jetting too rich?

You probably won’t need to worry about your bike running too rich after putting an aftermarket exhaust system on it. However, here are the symptoms of a bike that is running rich, just in case this comes up:

• Hard to start (when hot)
• Sputters or hesitates (at high RPMs)
• Fouled spark plug (or fouls often)
• Poor throttle response overall
• Loss of power

With this in mind, you can either adjust your current settings or purchase new jets.