Kawasaki KLX300SM & KLX300DS Full Single Exhaust System

Barker's Performance

$ 569.00

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Snapshot Kawasaki KLX300SM/Dual Sport Features:

  • Fits 2021+ SM and Dual Sport Models (300R exhaust can be found here)
  • Comes standard with a 12" round silver muffler, black tag, and a silver turn down tip
  • Upgrades available include longer 14" muffler, black powdercoat on the muffler, different tag colors, different tip configurations** 
  • Black billet exhaust clamp and support bar to strengthen exhaust perch mount are included
  • O2 bung installed for factory sensor
  • 19% Peak Power Increase with the stock intake
  • 24% Peak Power Increase with modified intake
  • Tuned megaphone style headpipe
  • 3lb weight reduction over the stock pipe
  • Optional Add-Ons:  Quiet Core, Spark Arrestor, Power Commander Fuel Controller, EHS Racing Fuel Controller

**This exhaust comes standard with a turn down tip. You may choose a billet tip if you prefer, but it could melt the stock turn signal. The exhaust muffler length contributes to the sound level. If sound is a concern for you, the 14" muffler is more quiet than the 12"; the turndown tip also sends sound down to the ground vs. straight out the back of the machine with the billet tip.

The Full Story:

The KLX300SM is an awesome, nimble, and reliable Supermoto just perfect for an exhaust upgrade. We began fielding requests to build a pipe for these bikes when they were released, following our great success and power gains we've had on the KLX250 machines. We were fortunate enough to find a 300SM at a local dealership and purchased it to get started on a potential pipe design. Right out of the gate we noticed the KLX300 & KLX300SM are woefully disappointing in the horsepower department, so we set out to build an exhaust system and tuning package that can make these bikes a little more fun to ride. With a stock exhaust outlet about the size of your pinky finger we knew there was great potential to open the exhaust up and let the motor breathe.

As with all of our new exhaust builds, we hit the dyno with a combination of different header configurations looking to find the best pipe to suit the 300. After multiple head and mid pipe combinations we were satisfied we found the highest performance gaining setup. In these initial stages we didn’t have fuel controller options but based on the stock fuel mapping the gains were tremendous with the final pipe design we settled on. The design added 2hp down low and 4hp peak and above 8,000 rpm’s carrying the horsepower much further to nearly 8-10hp at redline with pipe alone. Wanting to see what was fully capable, we removed the snorkel first and made a few dyno runs revealing that the bike gained a touch more with more airflow. When we fully removed the airbox lid we found it gained quite a bit more yet, leaving the highest gain hp runs we had seen so far. An open lid and our full exhaust system peaked at nearly 27hp at 8,000rpms. Down low without the lid we gained a nice 3-4hp but clearly lean and needing a fuel controller.

With fuel controllers in hand we were back at the LaBaron’s Powersports dyno again to build our custom fuel maps and finalize our tuning and testing. Our bone-stock KLX300SM produced 20.34 horsepower at the wheel for our baseline runs. We found the bike really struggles to crest 16hp below 7000rpm and then all of the sudden, a "2-stroke like" power curve kicks in out of nowhere. Installing the Barker's exhaust pipe and keeping the stock airbox lid, we gained 2-3 additional horsepower below 7000rpm, 4.6 more horsepower at peak, and 8-10 more horsepower at redline with a much flatter curve from 7-10.5k.

Air/fuel ratios even with the stock airbox lid and our pipe showed a few spots that leaned out a bit at some of the lower cruising rpms so we do recommend a fuel controller. We tested and developed maps for two different tuning options, both with and without the airbox lid. Correcting the lean fuel trim is not an option on this machine as it goes dangerously lean at the low to mid throttle openings once the intake is opened up. Ultimately, the airbox lid removal is good for an additional 1.5-2hp throughout the curve and with the proper tuning, you can see a drastic improvement in power from idle to the rev limiter. Our final results with pipe and modified or removed airbox lid were 2-4hp increases below 7000rpm, nearly 6.3 more peak horsepower, and nearly 11hp more at the rev limit. The curve from peak to readline is almost completely flat, where it used to nosedive on the stock setup. Above 8,000rpms the gains run from 20-40% nearing redline.

In summary, the bike responds very well to installing a Barker's exhaust and gains a substantial amount of horsepower. Gains are everywhere in the curve and really take off up top in the over-rev. Modifying the snorkel to a KDX 200 snorkel or removing the lid entirely gains another few horsepower but definitely requires tuning. In the end, running a KDX Snorkel or open lid, our pipe, and custom mapped PCFC or EHS fuel controller gained an unreal 6+ horsepower going from 20.34 to 26.61 peak horsepower and much more in the over-rev where the stocker used to fall flat. We were able to smooth out some of the abrupt "2nd powerband" to make a smoother transition once it hits that 7k mark removing the dead spot. It is still there though, and we have determined that it is due to the machine's camshaft profiles. In summary, the motor loves to rev, and is most happy between 7000rpms and the rev limiter, but if you enjoy your KLX300SM and just would like 15% or more power everywhere, then this is the solution for you.

Independent Dyno Tuning & Testing completed by Alex at LaBaron's Powersports in Imlay City, MI and Eric at EHS Racing in Rockingham, NC.