Exhaust FMF Factory Fatty SX 125 / 150 2004-2010

FMF Factory Fatty Exhaust

The FMF Factory Fatty is one of the most popular 2-stroke motocross exhausts. With its "Factory" look and high performance, it has solidified its position as a prominent choice in the motocross community.

Factory Fatty performance

The Factory Fatty exhaust from FMF improves the performance of your motorcycle across the entire RPM range. The power is delivered as linearly as possible and is significantly higher than with the original exhaust, which also breaks in at the upper RPM range. The Factory Fatty creates the widest possible power band.

This exhaust is suitable for both motocross and supercross. However, the Gnarly is more suitable for enduro.

• Body: Lightweight 0.95mm steel
• Manifold: 1.11mm thick steel
• O-rings are included for most models
• Hand hammered welds
• Untreated finish for a pure factory look

If you want the same performance but find the factory finish too high maintenance, then the nickel-plated Fatty would be a good alternative.

For a top sound, we also offer a large selection of FMF silencers, from the Shorty for Supercross to the ultra-quiet Turbinecore for Enduro.

Exhaust scooter, moped, motorcycle

The exhaust has a major influence on the performance of scooters and mopeds. By replacing the original with a tuning exhaust, you can improve the gas flow and increase the engine power.

exhaust parts

• The headpipe or header is the connection between cylinder and exhaust, and an exhaust gasket provides the necessary seal. In street-legal systems, the headpipe is equipped with a legally required restriction. Some people remove this restrictor to increase power.
• The actual exhaust body or expansion chamber is connected to the header pipe. In a classic 2-stroke expansion chamber type exhaust, gas pressure waves are used to improve engine performance.
• At the end there us the silencer or muffler that discharges the exhaust gases and, with the help of damping wool, also reduces the noise generated by the vehicle.

Replacing the exhaust

For 2-stroke engines, various settings and components usually need to be adjusted when the original exhaust is replaced with a tuning version. These changes include:

• Adjusting the carburetor by replacing the main jet.
• Upgrading the clutch or replacing the clutch springs.
• For scooters, it may be necessary to reduce the weight of the variator weights.