You’ve heard me talk a lot about how stock muffler systems are pretty damn good right? Usually I say something like, “the stock 2018 Yamaha YZ450F muffler system is hard to beat”, but that quote doesn't stop me from trying to see if there is something better out there. I am a fan of MXGP’s and seeing the Akrapovic mufflers on the Yamaha’s of Romain Febvre and Jeremy Van Horebeek got me thinking I wanted to try one of these beautiful looking systems. After some scouring, I found a US connection and got one delivered to give it a test ride.
First off the Akrapovic Evolution muffler system is one of the most beautiful looking systems made 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. The Akrapovic Evolution titanium muffler system is 1.5 pounds lighter than the stock system and tucks under the right side panel very nicely. 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 Akrapovic muffler uses an aluminum spacer in the rear hole to give the muffler enough clearance (from the brake caliper) once the suspension is full collapsed. 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 slightly quieter than the stock system. I started the test with the “TP map” installed inside the 2018 YZ450F (if you don’t know what the TP map is, email me at firstname.lastname@example.org). Roll on power delivery was smoother out of corners with the Akrapovic and “TP 1.0 map” installed compared to the stock system and “TP 1.0 map”. I didn’t really like the smoother delivery and I wanted to get some bottom end delivery back, so I went to the TP 2.0 map. Doing this helped me get some of the RPM response and bottom pull that I wanted back from the Yamaha out of corners. If you feel like you want a smoother delivery or ride hard pack you may want to leave the “TP map 1.0” installed with the Akrapovic. The Akrapovic system really comes alive once out of the corner as the Yamaha starts pulling harder and longer than the stock system down straights. Second and third gears can be stretched longer by the rider and once the TP 2.0 map is installed back in the bike (with the Akrapovic) rolling third gear in corners is slightly easier on the rider as well (with 49 tooth rear sprocket). Over-rev is slightly better through each gear with the Akrapovic and the overall engine feels like it revs a little quicker. The Akrapovic also gave the Yamaha YZ450F a free-er feel and takes away a little engine braking sensation on de-cel.
In conclusion, I feel the Akrapovic Evolution muffler system is an excellent system once going back to the TP 2.0 Yamaha Power Tuner 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. Akropvic’s website is a very informative, clean, and one of the best aftermarket muffler websites to browse around on if you got the time. There are dyno charts, a sound tool that lets you compare the stock system to Akrapovic’s muffler sound, 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 about an hour!
If you have any questions about this test please feel free to email me at email@example.com.