FMF Factory 4.1 Mini Exhaust Full System

The Mini Factory 4.1 Full System Exhaust styling similar to 4.1 RCT big bike products, with an aggressive look and sound (only lacking the big bike model's internal resonance chamber module).

The Factory 4.1 achieves a shorter overall length that is less susceptible to crash damage and complementary to the Factory Forward Engineering - moving the muffler(s) 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.

• Massive POWER gains throughout the RPM range.
• Quieter than stock.
• Huge weight savings.
• Stainless steel header and end cap.
• Includes combination Quiet / Spark Arrestor insert.
• New RTS (Rapid Tuning System) makes for easy sound insert changes as well as adding U.S. Forestry Service Approved Spark Arrestor.
• #1 Exhaust in AMA Supercross Series, AMA Motocross Series, FIM Motocross of Nations and the Monster Energy Cup!
• The Factory 4.1 is constructed from only aerospace-grade materials that meet FMF's exacting specifications and 100% manufactured at their Southern California factory.