FMF 042380 Mini Factory 4.1 RCT Full Exhaust System Aluminum

The FMF Mini Factory 4.1 RCT is a complete performance exhaust system engineered specifically for mini dirt bikes. This full system delivers superior power gains throughout the RPM range while maintaining a quieter sound output than stock exhaust systems.

Resonance Chamber Technology:

The Factory 4.1 RCT incorporates FMF's patented Resonance Chamber Technology both internally and externally. The patent-pending core shape enhances and refines exhaust pressure waves for optimal power output while reducing sound levels. The patented canister shape increases internal volume to accommodate more sound-absorbing material.

Key Features:

• Natural aluminum muffler with stainless steel header and end cap
• Single inlet/single outlet configuration with wrapped perforated core design
• Factory Forward Engineering positions the muffler closer to the motor, centralizing mass and reducing crash damage susceptibility
• Oval-shaped tip with slant cut in 304 stainless steel with natural finish
• Includes spark arrestor screen insert for trail-legal riding
• QuietCore 94dB insert available separately for additional sound reduction
• Easy maintenance with 4-screw front end cap removal
• 100% American-made from aerospace-grade materials at FMF's Southern California factory
• Complete hardware included for bolt-on installation

The rear endcap features a snap ring design that allows for simple tuning adjustments with optional inserts and spark arrestors. This system provides massive weight savings over stock while delivering the quality, craftsmanship, and performance expected from FMF Racing.