Great power, a great look and that factory sound By the staff of Dirt Wheels
With the EPA controlling the OEMs with corked-up exhaust systems, it can really bum a rider out. The high-performance engines of today have a lot of potential, but that potential can be robbed by the stock exhaust. Luckily for us closed-course racers there are aftermarket companies like FMF that build quality exhausts that sound amazing and unleash the ponies that the OEM exhaust keep fenced in.
The FMF Factory 4.1 RCT full exhaust system is handmade here in the USA with some quality materials. The muffler is made from titanium, which is anodized in blue and the end cap is made from carbon fiber. The MegaBomb head pipe and mid-pipe are made from stainless steel. All of these materials together make for a lightweight and very strong exhaust system. The full exhaust system weighs 4.7 pounds according to FMF. A stock exhaust is usually made from steel and weighs anywhere from 7 pounds to 10 pounds depending on the model.
PURE AMERICAN POWER
The challenge for FMF was to make a noticeable power increase for high-performance four-stroke sport ATVs. With many trips to the track and constant dyno runs, they really hit it out of the park with this exhaust system. It usually takes about 20 minutes to remove the stock exhaust and install the 4.1 RCT system. Along with that we had to re-jet the carburetor on the Honda TRX450R, and we removed the airbox lid. With all of these changes, our 450R had a big attitude change. Acceleration was the first thing that we noticed; it carried more speed and power through the entire powerband. Power comes on smooth with additional but more rideable power. One of the best parts is the sound from the FMF; it’s throaty but not overly loud—just crisp and clean. Getting the front end up over obstacles was a breeze with just a stab of the throttle, and having that kind of rideable power made us less tired since we had to manhandle the bike more often before the FMF exhaust and the correct jetting. All of these great features added together make this exhaust a worthy add-on for any sport ATV. This exhaust is on the expensive side at $774.99 for the TRX450R and the YFZ450R. However, as the old adage goes, “You get what you pay for.” With weight savings like this, produced tough in the USA and an increase in power, you will have many years of enjoyment with this trick-looking exhaust. To order your own FMF 4.1 RCT full exhaust system, visit www.fmfracing.com or call (310) 631-4363.