Nowadays on most 450cc four-stroke motocross bikes, the majority of riders aren’t looking to add much power, if any, because the bikes come stock with so much horsepower and torque. Most 450 riders who install an aftermarket exhaust system are mostly aiming to make the power more usable or shift the power curve to a different part of the powerband. In fact, the exhaust systems that come on these machines are designed and made so well that it’s actually difficult for aftermarket companies to improve upon them.
The all-new 2018 Yamaha YZ450F produces a lot of power and I’m not looking to add massive amounts of raw power to the bike. In stock form, the bottom-end hits quite hard, and after a long day of moto, it can be a little too much. With that in mind, I sought out an aftermarket exhaust system to see if I could smooth out that bottom-end hit, and I opted for Akrapovic’s Evolution Line full titanium exhaust system.
The first thing I noticed about the Akrapovic came when I took it out of the box. I couldn’t help but admire how amazing the system looks. From the welds to the machine work and the fit and finish, this pipe may very well be one of the best-looking pipes I have seen. In addition to being easy on the eyes, the Akrapovic fit perfectly and was very easy to install.
After installing the pipe, I did what just about all of us do when changing exhausts systems, that is starting the bike and doing a sound check. I instantly noticed the YZ was a little bit quieter and I like that seeing as I already ride with earplugs. It also had more of an aggressive bark when the bike was revved, which was awesome. After all, who doesn’t want a great-sounding pipe?
What I noticed most about the Akrapovic on the track is that it makes the YZ450F powerband a little more usable. It smoothed out the initial hit from the crack of the throttle to make it more of a smooth transition from off-throttle to on-throttle. This is exactly what I was looking for in an aftermarket pipe and Akrapovic not only did a great job with making the bottom-end hit a little easier to manage, but it also added some power in the midrange and top-end. With the Evolution Line, I noticed my arms felt a lot less tired at the end of the day than they normally did with the stock system installed as a result of the smoother bottom-end hit the Akrapovic delivered.
On top of the improvements in power delivery and output, the Akrapovic also sheds some weight over the stock unit. The Evolution Line system saves 1.5 pounds over the stock system with the Akrapovic weighing 7.5 pounds and the stock unit coming in at 9 pounds. Any weight savings on the upper area of a motorcycle is much more noticeable in comparison to weight savings on the lower areas of the bike, so on top of decreasing the overall weight of the motorcycle, shedding weight in key areas can make even more of a difference too.
All in all, Akrapovic did an excellent job of making the bottom-end smoother but not taking any power away, and adding slightly more pull in the midrange and top-end areas of the powerband. The Akrapovic Evolution Line exhaust system retails for $1,308, and I would highly recommend it to anyone looking at an aftermarket pipe for their 2018 Yamaha YZ450F.