Overall, the 2017 Kawasaki KX450F engine has a fairly linear powerband. I like that a lot about the bike because it makes it easy to ride due to how predictable the power is. However, if there was one area the power does come on a little suddenly and strong, it would be the transition from the bottom-end to the midrange. I believe this is because the stock bike lacks a little bit of bottom-end. Accordingly, I wanted to get a little more oomph out of the engine in this area, especially for deep and loamy corners. To do so, I opted to install an Akrapovic Evolution Line full exhaust system.
The header pipe and muffler are made from titanium and the heat shield on the resonator from carbon fiber. Swapping the stock exhaust system for the Evolution system took about 20 minutes. I torqued all of the bolts to the specifications provided in the installation instructions and installed the springs on the header pipe and the exhaust flange. Like any full titanium exhaust system, putting a coating of anti-seize (or grease, in my case) on the rear of the header pipe where it meets the muffler is essential so the two parts don’t become stuck together from heat and then become a real challenge to remove.
Upon starting the bike, I immediately noticed a quieter and less raspy-sounding exhaust note, which was a great change. On the track, the pipe made the powerband smoother from bottom to top. Instead of adding bottom-end power, the pipe made the entire powerband smoother, which made the KX450F a bit easier to ride thanks to the more gradual power curve. This was especially true later on in the day when the track became more dry and hard-packed, as I didn’t have to be as cautious with my throttle hand for fear of spinning the rear wheel.
As for looks, the system is top materials and top-quality construction. You won’t find a better-looking system. One minor complaint I had is that one of the bolts on the heat shield came out after my first moto testing it, so I had to find a spare similar bolt to make do for the rest of the day. I made sure to tighten both bolts a little more snugly than the torque specs to ensure it didn’t happen again (and it didn’t). The Akrapovic Evolution exhaust system on the Kawasaki KX450F is an ideal pipe for a rider who is looking to gain more user friendliness and rideability out their KX450F, who wants their bike to look and sound way better, and who has the money to buy in at this level of materials and quality.