FMF Racing Mini Factory 4.1 Slip-On Mufflers

FMF Racing's Mini Factory 4.1 slip-on mufflers styling is 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 mufflers closer to the motor to centralize mass. Visible changes to the exterior include a redesigned canister to increase internal capacity for maximum volume of packing material—which itself is a proprietary blend formulated for superior durability and sound attenuation. The rear endcap has been engineered to provide simple tuning adjustments, incorporating a snap ring feature to secure both the standard and optional inserts. Key features and benefits: * Available in stainless steel or FMFs exclusive Ti-Metal construction * Lightweight—offering huge weight savings * Massive power gains throughout the rpm range * Factory Forward Engineering centralizes mass—improving handling * RTS (Rapid Tuning System) for quick and easy trackside tuning * Tuned exhaust with optimized core specifications for each application * Patented core shape lowers sound level while maintaining maximum power output * Patented canister shape increases internal volume for more sound absorbing material * Quiet insert included (94db) * Removable spark arrestor included on most models * Can be used with FMF or stock OEM header Show Less