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 Ti YZ250F 14/18 Full System w/carb end cap []](https://boydsassets.specd.nz/uploads/2026/09/7b0e26a9-0713-42c8-8c51-be5f0aed11af-jpg.webp)
![4.1 RCT Ti YZ250F 14/18 Full System w/carb end cap []](https://boydsassets.specd.nz/uploads/2026/09/2c786e47-e70c-409e-b231-6ab960aa48d1-jpg.webp)
![4.1 RCT Ti YZ250F 14/18 Full System w/carb end cap []](https://boydsassets.specd.nz/uploads/2026/09/aca384a4-ec9d-41e3-a92b-d574cebbe7e1-jpg.webp)
![4.1 RCT Ti YZ250F 14/18 Full System w/carb end cap []](https://boydsassets.specd.nz/uploads/2026/09/86a8f753-ae2f-4fd6-8364-0506be0d983e-jpg.webp)
![4.1 RCT Ti YZ250F 14/18 Full System w/carb end cap []](https://boydsassets.specd.nz/uploads/2026/09/f0ef6f3d-5b97-4551-8d2c-df0378ac975c-jpg.webp)




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