The Factory 4.1 RCT incorporates the latest in FMF Resonance Chamber Technology both internally and externally. It starts at the center with a new core - a patent pending shape enhances and refines the exhaust pressure wave for optimal power output while lowering the sound level. In addition, it achieves a shorter overall length that is less susceptible to crash damage and complementary to the Factory Forward Engineering - moving the muffler closer to the motor to centralize mass. Visible changes to the exterior include a redesigned canister to increase internal capacity for the maximum volume of packing material. The packing itself was not overlooked - a proprietary blend formulated for superior durability and sound attenuation. The final component is a new rear endcap engineered for simple tuning adjustments incorporating a snap ring feature to secure the standard and optional inserts. The Factory 4.1 RCT is constructed from only aerospace grade materials that meet FMF's exacting specifications and 100% manufactured at their Southern California factory.
Massive Power gains throughout the RPM range.
Quieter than stock.
Huge weight savings.
New RTS (Rapid Tuning System) makes for easy sound insert changes as well as adding US Forestry Approved Spark Arrestor.
Can be used with FMF header or stock.
No. 1 Exhaust in 2011 Supercross Series, 2011 Motocross Series, 2011 Motocross of Nations and 2011 Monster Energy Cup!
The science behind the Megabomb header may be FMF's greatest engineering accomplishment to date. You can bolt on a Megabomb for as much as a 3 hp boost, plus the Megabomb actually reduces noise levels by as much as 1.5 dB. Used by Factory Teams, the Megabomb is the next level technology you can have today.
Produces long header torque and short header over-rev.
Reduces sound output as much as 1.5 dB.
Increases output from stock motor as much as 3 HP, alone.