The decision to purchase an aftermarket exhaust for a four-stroke dirt bike is getting tougher each year. Current sound restriction laws combined with the already high tech factory exhaust designs don't leave a lot of options for those of looking for more performance without the price of a thundering exhaust note. Dirt bikers who are riding in public areas and off a closed course should want to keep their exhausts as quiet as possible out of courtesy and the desire to protect our right to ride responsibly. FMF has developed their "Q" Exhaust system with a claim of meeting the current sound requirements and yet still yielding performance gains.

For our 525EXC project bike we opted for the complete "Q" System, which comes with the two into one header pipe, the PowerBomb mid pipe and the "Q" Muffler. The PowerBomb mid pipe is a type of "Pre muffler" that creates more surface area to absorb exhaust sounds while increasing actual exhaust flow by nearly 10%. After the mid pipe the exhaust makes its way to the "Q" muffler where internal baffles, chambers and sound absorbing material are said to disperse the sound and enhance the exhaust flow dynamics. From there the exhaust runs through the built in "bullet" type spark arrestor and out the performance flow end cap.

After receiving the system my first impression was the system is very high quality but the installation instructions need improvement. Now I will admit putting on an exhaust system isn't a tough job and the "Q" muffler does use universal type straps so the instructions are probably meant to cover a variety of installations. Even with this being the case the directions where made up of a few different sheets that didn't flow together and lacked any useful tips or photographs. I think for the price of this exhaust system FMF could make a set of directions that is easier to follow, specific to your order and include a few visuals.

The overall installation procedure is very simple and straightforward but be ready for those dreaded muffler straps! I began by removing the stock exhaust system and installing the new two-into-one header. I put on a little high-temp silicone, KTM Orange of course, to make sure of a good seal between the header and the exhaust flange off the cylinder. Although the photo looks like I went overboard I just peeled the excess away after it dried up. From here I hooked up the stock springs using vice grips, although a spring puller would have made it a little easier.

Next I slid the PowerBomb mid pipe into place on the header, also using a little high-temp silicone to prevent any exhaust leaks. The mid pipe slides right on and is then held in place by using the supplied springs and bolt threaded in lightly for later alignment. I found it easier to remove the lower shock bolt than to try and stuff the pipe between the shock spring and the frame. After doing this I had no alignment problems with the springs or mounting bolt.

From here things start to get heated, literally so grab an air conditioner and towels because you will sweat. The "Q" muffler slides onto the mid pipe without a hitch and even the supplied springs go on fairly easily with the help of vice grips. Putting on the clamps isn't a fun job and would be easier with two people, one to work the clamps shut while the other person gets the bolt threaded in place. Since it was after hours -I had to improvise and use the trusty vice grips with a towel to hold the clamps closed and avoid scuffing them up. A couple spacers are included in the kit but I only ended up using the one for the rear most clamp. Although the instructions said to use the smaller spacer for the front I couldn't get it to line up properly and felt I was risking thread damage if I tried to force it. Without the front spacer it went together much easier and still seemed to have plenty clearance from the rear tire.

With the complete system on the bike I just finished off by tightening down the pipe hanger bolt on the mid pipe and reinstalling the lower shock bolt. The fit and finish on the entire system is very good and everything lined up much better than I expected. It didn't require any forcing or modifications like I have heard some of the other systems sometimes require.

So how did it work? Well so far I have only ridden with the pipe out at the Elsinore MX Park on the Vet and GFI tracks. The system definitely delivers a deeper and throatier sound over stock. I didn't think it was any louder than stock but it takes on a different sound. The power on the bottom and midrange was improved over stock. Coming out of turns onto the tabletops and short straights the bike pulled harder than stock into a meatier midrange. I would use the word "thicker" power to describe the seat of the pants feel. Top End? Well I can't comment yet because I haven't had the chance to get the bike opened up. Don't panic though we have a desert outing planned soon.

Since this is a project bike check back for updates on any jetting changes and further feedback on performance in different conditions. We would like to test the bike against a stock system to get a fair comparison of the improvements. I might also try to get a forest ranger to do a sound check reading for us to get a db reading.

FMF website article link on Noise testing: http://www.fmfracing.com/dirtrider.htm

http://www.fmfracing.com

Since our initial install and overview of the FMF system we have had the opportunity to get in a few good desert trips. After riding a few other bikes with stock systems we noticed several things. First is that the Q seems to actually rev a little slower that the stock muffler. When riding the different bikes it feels like stock bike is a little more free revving whereas the Q system sort of spools itself up into the revs with a more torquey feel.

The next thing we noticed is that although the Q seems to take longer to build revs it offers more torque right off idle and into the midrange. Where the stock system takes a while to build into the strong midrange surge of power the Q system starts to build it much earlier. All of this can be either good or bad depending on what type of power you like, what terrain you ride and the actual conditions. I tend to ride the low to mid range portion of the power range the majority of the time and only get on the bike hard on the top-end when in deep sand washes or high-speed straights. For me this system is great, especially in really tight rocky or sandy canyons. Other riders who like to ride in the upper range of the power may actually appreciate the stock system over the Q since the bike seems to get into the upper part of the power range a little quicker.

Finally, since the Q points its exhaust at a different angle than the stock muffler it torched the right side blinker after about three long desert rides. Pulling up to the Whitehouse Saloon in Randsburg to get some grub I hopped off the bike only to see two wires hanging from the poor melted back housing of the once complete blinker. A friend with the same problem has tried putting on some reflective heat tape along with a small piece of aluminum and had successful results. We are going to buy a new blinker and give this a go to see how it holds up.

Overall the FMF Q System has been a great addition to the 525 project bike. The fit and finish on the pipe are holding up excellent and the system gives the bike a different look from all the other KTMs running around these days. We have received numerous compliments and questions from other riders out in the desert. If you're a rider who likes the quick revving of the stock bike and spends the majority of the time in the upper range of the power then the stock or another system may be the best option. On the other hand if you favor the low to midrange type of power increase then the FMF Q system will give you increased torque in those areas with a very controlled power delivery and still meet the strict sound requirements of today.