The Akrapovic Evolution muffler system is one of the most beautiful looking systems out there in the market today, is well built, and has quality welds all the way around it. Once hot, the titanium color of the headpipe is the most dynamic blue you will ever see from any muffler manufacturer, which just makes you feel that much more factory on the starting line right? The Akrapovic Evolution titanium muffler system is 1.5 pounds lighter than the stock YZ450F system and tucks under the right side panel much cleaner than other systems that are on the market. When putting on the system, make sure to leave the headpipe loose and then connect the mid pipe, so that the slip fit joint slides in easily. Once those two pieces are connected, tighten the headpipe bolts and mid pipe bolt just snug. The Akrapovic uses your existing stock heat shields or you can purchase carbon heat shields separately. The Evolution muffler uses an aluminum spacer in the rear hole to give the muffler enough clearance (from the brake caliper) once the suspension is fully collapsed. This system is one of the easiest to install and I have been putting a ton of systems on this blue bike lately. I did notice that there is a small screen deep inside the core of the muffler, however I was told that this isn't a spark arrestor, but a noise insert. Note: Leave the insert in, as the muffler performs better with insert in and is much pleasant to the ear. Once rear section (muffler) was installed, I went around and tightened up the remaining bolts. Doing it this way ensures there is absolutely no binding going on between each slip fit joint.
Out on the track the Akrapovic Evolution muffler has a deeper sound and is much quieter than the stock system. I started the test with the “TP 3.0 and stock” maps installed inside the 2021 YZ450F (if you don’t know what the TP 3.0 map is, email me at kris@keeferinctesting.com). Roll on power delivery was smoother than stock out of corners (with either map) with the Akrapovic, compared to the stock system. I have grown to love the smoother roll on power that the Evolution system delivers as it really helps me roll my corners better without getting the chassis upset. The connectivity of the Akrapovic muffler is second to none as you will notice more rear wheel connection under heavy throttle.
The Akrapovic system really comes to life once out of corners as the Yamaha now starts pulling harder and longer than the stock system down straights. Second and third gears can be stretched longer by the rider with the Evolution system and rolling third gear in corners is slightly easier on the rider as well (with stock gearing). Over-rev is better through each gear with the Akrapovic and the overall engine feels like it revs a little quicker/freer. The freer feel takes away some engine braking sensation on de-cel and also helps the Yamaha handle slightly better coming into corners. Yes! All from a muffler!
In conclusion, I feel the Akrapovic Evolution muffler system is an excellent system once you can dial in your favorite desired Yamaha Power Tuner App setting. You will not be getting more bottom end than a stock system, but the gains through the mid-top end are a noticeable difference. It will be up to you if that difference is worth the $1300.00 you will spend on the Evolution titanium system. Akrapovic’s website is a very informative, clean, and one of the best aftermarket muffler websites to browse around on if you have the time. There are dyno charts, a sound tool that lets you compare the stock system to Akrapovic’s muffler pitch, documents of replaceable parts, and technical data about the system itself. You can head over to akrapovic.com and punch in what bike you want to geek out on. I did, for a while!
Extra Credit: If you’re like me and still want more power yet even more connectivity, look at getting a Vortex ECU mapped by Chad at XPR Motorsports for this 2021 YZ450F. You might think that putting a Vortex on a YZ450F is over kill but what you're getting is a faster, yet easier to ride Yamaha that will allow you to ride it harder. Less on/off feel with this muffler system and the Vortex ECU. I have created a couple maps with Chad on this Vortex and along with this system has made this machine easier to ride. I have let other R&D test riders ride my test bike with these two mods on and they were blown away.
Email me if you have any questions or concerns about this test kris@keeferinctesting.com.