Description

The Factory 4.1 RCT incorporates the latest in FMF Resonance Chamber Technology™ both internally and externally. In addition, we achieve a shorter overall length that is less susceptible to crash damage and complementary to our Factory Forward Engineering – moving the muffler closer to the motor to centralize mass. The Factory 4.1 RCT is constructed from only aerospace grade materials that meet our exacting specifications and is manufactured 100% at our Southern California factory.
- Available in Natural Aluminum Muffler with Carbon End Cap
- Massive Power gains throughout the RPM range.
- Huge weight savings
- New RTS (Rapid Tuning System)
- FMF uses the highest quality proprietary blend of alloy grade titanium made especially to our standards.

![4.1 RCT S/S 450SX-F 16-18 FMF Full System w/carb e/Cap []](https://boydsassets.specd.nz/uploads/2026/09/4418a5f1-ca7b-4855-8041-2c56de432dd9-jpg.webp)
![4.1 RCT S/S 450SX-F 16-18 FMF Full System w/carb e/Cap []](https://boydsassets.specd.nz/uploads/2026/09/3f11a1ce-7294-48f8-97e1-45fb13d9fed4-jpg.webp)
![4.1 RCT S/S 450SX-F 16-18 FMF Full System w/carb e/Cap []](https://boydsassets.specd.nz/uploads/2026/09/0db27e40-b096-463e-8598-a1b0dfe5bcc6-jpg.webp)
![4.1 RCT S/S 450SX-F 16-18 FMF Full System w/carb e/Cap []](https://boydsassets.specd.nz/uploads/2026/09/888454a6-0a87-4a83-a671-a77cd56504e7-jpg.webp)
![4.1 RCT S/S 450SX-F 16-18 FMF Full System w/carb e/Cap []](https://boydsassets.specd.nz/uploads/2026/09/0ae6c8d3-b1c4-410d-88ba-d86be1f2b306-jpg.webp)




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