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 with Carbon Fiber End Cap
- Massive Power gains throughout the RPM range.
- Huge weight savings
- New RTS (Rapid Tuning System)
- FMF uses the highest quality proprietary blend stainless steel made especially to our standards.
PN#045662
FITMENT:
2020-23 HUSQVARNA 501 FEs, FE
2020-23 KTM 500 EXC-F, XCF-W
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Sound levels at idle speed tested at 1' above and 1' behind each
muffler on the same 21' 500 EXCF tested back to back.
Stock muffler 82
Stock w Pro Moto end cap / ultra silent insert 85
Stock w Pro Moto end cap / silent insert 86
Stock w Pro Moto end cap 88
Graves Motorsports w db killer 85
Graves Motorsports 89
Fmf q4 84
Fmf 4.1 88
Fmf power core 88
Lexx w db killer 86
Lexx w spark arrestor insert 87
Lexx 89
Akropovic 85