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.
- Can be used with FMF or Stock OEM Header

![I 4.1 Dual Ti CRF450R 2017-18 w Carb/Cap Slip Ons FMF []](https://boydsassets.specd.nz/uploads/2026/09/44b7c2c9-7b5d-4fc2-82c0-a6256cc6572b-jpg.webp)
![I 4.1 Dual Ti CRF450R 2017-18 w Carb/Cap Slip Ons FMF []](https://boydsassets.specd.nz/uploads/2026/09/21ef5207-ce85-43b1-8da8-b3ee5b9a6e89-jpg.webp)
![I 4.1 Dual Ti CRF450R 2017-18 w Carb/Cap Slip Ons FMF []](https://boydsassets.specd.nz/uploads/2026/09/335a2ae0-ed3c-43d8-972e-eeb4ed65a787-jpg.webp)
![I 4.1 Dual Ti CRF450R 2017-18 w Carb/Cap Slip Ons FMF []](https://boydsassets.specd.nz/uploads/2026/09/46d854f4-7eed-48e4-abcf-db3635e57bf0-jpg.webp)
![I 4.1 Dual Ti CRF450R 2017-18 w Carb/Cap Slip Ons FMF []](https://boydsassets.specd.nz/uploads/2026/09/ff719698-1ef9-4d1e-af04-70170067767b-jpg.webp)
![I 4.1 Dual Ti CRF450R 2017-18 w Carb/Cap Slip Ons FMF []](https://boydsassets.specd.nz/uploads/2026/09/9da30f11-4963-45f0-bf48-15421e4d553c-jpg.webp)
![I 4.1 Dual Ti CRF450R 2017-18 w Carb/Cap Slip Ons FMF []](https://boydsassets.specd.nz/uploads/2026/09/ef1d9eca-a8e6-4dde-80b2-0e767e70bd82-jpg.webp)




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