The FMF Q4 S/A Hex Exhaust Muffler, manufacturer part number 044426 and vendor part number 79-4189, is designed for select Yamaha four-stroke off-road motorcycles. This performance muffler incorporates internal baffles, chambers, and advanced sound-absorbing materials to help accelerate exhaust flow while reducing noise and minimizing power loss.
Built for riders who need dependable trail and competition performance, the FMF Q4 S/A Hex features a United States Forest Service-approved spark arrestor with a maintenance-free stainless steel screen. Its sound output remains well below 96 decibels on most machines, helping meet strict off-road sound requirements while maintaining a responsive exhaust note and practical trail compliance.
Fitment includes the 2014–2017 Yamaha YZ250F, 2015–2017 Yamaha YZ250FX, and 2015–2017 Yamaha WR250F. Verify the motorcycle model and year before installation to ensure proper compatibility. The FMF brand and Q4 S/A Hex design provide a direct performance-focused replacement for riders seeking improved exhaust flow, controlled sound, and spark-arrestor protection.
Features:
- Performance exhaust design: Internal baffles, chambers, and sound-absorbing materials help improve exhaust flow with reduced noise and minimal power loss.
- Quiet operation: Sound output is well below 96 decibels on most machines to help satisfy strict off-road sound requirements.
- USFS-approved spark arrestor: Includes a maintenance-free stainless steel spark arrestor screen for trail-use compliance.
- Fitment: Fits 2015–2017 Yamaha YZ250FX, 2014–2017 Yamaha YZ250F, and 2015–2017 Yamaha WR250F.
- Product identification: FMF manufacturer part number 044426 and vendor part number 79-4189.
Fitment:
2014 Yamaha YZ250F
2015 Yamaha WR250F
2015 Yamaha YZ250F
2015 Yamaha YZ250FX
2016 Yamaha WR250F
2016 Yamaha YZ250F
2016 Yamaha YZ250FX
2017 Yamaha WR250F
2017 Yamaha YZ250F
2017 Yamaha YZ250FX
2018 Yamaha WR250F
2018 Yamaha YZ250F
2018 Yamaha YZ250FX
2019 Yamaha WR250F
2019 Yamaha YZ250FX