The Factory 4.1 incorporates the latest in FMF Resonance Chamber Technology™ (RCT) 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.
- Finished in Blue Anodized Titanium with Carbon End Cap
- Specially tuned and optimized for impressive power gains through the mid range to top end
- Impressive gains for MX, wide open desert riding and trails, super moto, snow bike and flat track
- FMF uses the highest quality titanium made specifically to our standards.
- Closed Course Use Only
- Spark Arrestor Quiet Insert included
- 4.2 lbs
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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
FITMENT:
045648
21+ GAS GAS EC-250/350F
20+ HUSQVARNA FE-250/350
21+ HUSQVARNA FE-350/450 ROCKSTAR EDITION
20+ HUSQVARNA FE-350/501
20+ KTM 350/450/500 EXC-F, XCF-W
045586
HUSQVARNA FC250 16-18
HUSQVARNA FC350 16-18
HUSQVARNA FC450 16-18
HUSQVARNA FE250 17-19
HUSQVARNA FE350 17-19
HUSQVARNA FE450 17-19
HUSQVARNA FE501 17-19
HUSQVARNA FX350 17-18
HUSQVARNA FX450 17-18
KTM250 EXC-F 17-19
KTM250 SX-F 16-18
KTM250 SX-F FACTORY EDITION 15-17
KTM250 XC-F 16-18
KTM350 EXC-F 17-19
KTM350 SX-F 16-18
KTM350 XC-F 16-18
KTM450 EXC-F 18-19
KTM450 EXC-F SIX DAYS 17-19
KTM450 SX-F 16-18
KTM450 SX-F FACTORY EDITION 15-17
KTM 450 XC-F 16-18
KTM 500 EXC-F 17-19