FMF Motorcycle

FMF Racing Motorcycle Exhaust: Five Decades of Performance Engineering

FMF Racing — short for Flying Machine Factory — has been synonymous with high-performance motorcycle exhaust systems since 1973. Founded by Don Emler Sr., a racer and tinkerer constantly in search of more speed, the brand was built on a simple idea: going faster meant having more fun. What started in a Southern California garage evolved into one of the most trusted exhaust manufacturers in the world, and that passion for performance has never wavered.

Race-Proven Products, Hand-Built in the USA

FMF still engineers and builds everything by hand, from the ground up in the USA. That commitment to craftsmanship is rare in today's market and speaks directly to the quality riders can expect from every pipe, silencer, and header that leaves the factory. Their goal to take the most advanced machinery to its limits by building the world's best-performing exhausts — and hand-making each product in America — speaks volumes of the stature FMF Racing has reached.

The brand's reputation was cemented early when pro rider Marty Smith won on an FMF-equipped Honda Elsinore, solidifying FMF's standing for high-performance, hand-crafted exhausts. For more than 50 years, FMF has continued to push forward and never wavered in its purpose, with world-renowned exhausts used by the sport's fastest teams and riders across the globe.

Flagship Product Lines for Motorcycles

FMF's motorcycle lineup covers both two-stroke and four-stroke applications with several standout product lines:

• Factory 4.1 RCT: The Factory 4.1 RCT incorporates FMF's Resonance Chamber Technology™ both internally and externally, achieving a shorter overall length that is less susceptible to crash damage and moves the muffler closer to the motor to centralize mass. It is constructed from aerospace-grade materials that meet FMF's exacting specifications and is manufactured 100% at their Southern California factory.
• PowerCore 4 & PowerCore 2: FMF manufactures complete systems, slip-ons, and pipes for 2-stroke and 4-stroke dirt bikes, as well as accessories like spring tools, plugs, and exhaust packing and wraps. The PowerCore series is a perennial favorite for riders seeking a bolt-on performance upgrade.
• Gnarly Pipe & Factory Fatty (2-Stroke): The FMF Factory Fatty is designed to unlock more power and a smoother ride, increasing horsepower output throughout the powerband, delivering stronger low-end and mid-range pull while also improving over-rev.
• Megabomb & Powerbomb Headers: FMF offers Megabomb and Powerbomb header and silencer systems for MX, ATV, and dual-sport applications.

Resonance Chamber Technology & Innovation

FMF's patented Resonance Chamber Technology allows for shortening the overall length of the pipe, which results in reduced probability of suffering from crash damage, and moves the center of mass closer to the engine to improve riding balance. Don and later his son Donnie Jr. came up with numerous patented innovations that are now widely used by competitors. This culture of invention keeps FMF at the forefront of exhaust engineering year after year.

Championship Racing Heritage

FMF Racing has served as the "Official Exhaust" of American motocross, and as one of the longest supporters of the Pro Motocross Championship, the Southern California-based manufacturer has become one of the sport's most iconic brands. The Factory 4.1 is championship-winning exhaust, used by the STAR Racing Yamaha Factory Team. Whether you ride motocross, trails, or dual-sport, FMF brings that race-derived engineering directly to your motorcycle.