Before I start this review I am going to go on a little rant here, so bare with me. Mufflers are always a hot topic when it comes to horsepower, especially when you get a new bike. I know a lot of riders out there get a muffler system before they even ride their new bikes! Ride your new bike and break it in before purchasing any muffler please! See what you're working with and purchasing, so you know if its better than stock. Because if it’s not better than stock, what is the reason you purchased it in the first place? To look cool. To drop some weight. Those two statements would be the only answers that are acceptable when someone asks you why you have a new muffler on that bike that has an hour meter that reads 0.1 hours. Ok moving on……..
When it comes to Yamaha motorcycles, Doug Dubach is a name that comes to mind immediately right? Doug has been a Yamaha test rider for 87 years and is almost that old, but don't tell him I said that. Seriously, Doug knows the ins and outs of the 2018 YZ450F like the back of his hand, so I was anxious to try his slip-on muffler when I reached out to him. However, instead of trying a full system I wanted to do something different and just try a slip on muffler system. A slip on system is only the rear section that keeps the stock headpipe and mid-pipe intact. I installed the DR.D stainless muffler system (that saves just over one pound compared to stock) in only 3.5 minutes.
I am very picky when it comes to mufflers and how they deliver the power to each bike I evaluate. The DR.D slip on keeps the stock feeling YZ450F bottom end pull intact, but maybe softens the low end RPM response just a tad. This is only noticeable on super loamy style tracks, but helped rear end traction feeling on hard pack style tracks. Losing a little RPM response and gaining some rear wheel traction is not a bad thing on this beast of an engine. I want to note how hard it is to build a muffler system that keeps the low end pulling power feeling of a stock 2018 YZ450F as I have tested several full muffler systems that had less bottom-end than stock. Where most of you will feel the difference between the stock muffler and the DR.D is mid range pulling power. The mid-range meat that the DR.D system delivers is impressive and gives you a better pull in second gear and helps the third gear transition when shifting. With the stock Yamaha system (with stock gearing) it was hard at times to carry third gear through corners, so shifting to third immediately after the corner was a must. With the DR.D system I have the freedom to leave the Yamaha in second through the corner and shift early without the blue machine falling off the power much. Or if you choose to run third gear in corners it picks up the power slightly earlier and helps lazier/lug heavy riders get out of the corner quicker with more rear wheel traction. Top end is also slightly increased over the stock muffler as you are able to hold each gear (well, to be honest the only gears I used was first through fourth) slightly longer. If you're looking for more over-rev this isn't the muffler you are looking for because the DR.D system keeps all of the stock feeling over-rev on the track and doesn't gain anything extra. This isn't a bad thing as the standard YZ450F power character revs out just fine.
The DR.D slip on stainless system is the best slip on system that I have tried on the 2018 Yamaha YZ450F and will only set you back $395.00. Not to mention that you’re not losing any horsepower and gaining some mid-top end, while getting some added rear wheel traction. The DR.D muffler system comes with quality packing, has a nice sound to it without it being obnoxiously loud, is easy to re-pack on your own and doesn't blow out quickly. If it comes time to re-pack and you don't want to do it yourself, Dubach has an exhaust packing service where you can send in your muffler and he will re-furbish it for you for a small fee. If you're wife is having a conniption fit about you spending more money on your new bike you can tell her you're saving around $600.00 by not going to a full system. You’re actually compromising and doing her a favor! You're welcome fellas! You can check out all of the mufflers that DR.D makes over at dubachracing.com.
If you have any questions about this test, please free to contact me at firstname.lastname@example.org