Exhaust Silencer FMF Factory 4.1 RCT — Yamaha YZ 450 F, WR 450 F, YZ 450 FX 2018–2027, carbon (4T)

The FMF Factory 4.1 RCT is FMF's flagship four-stroke silencer. RCT (Resonance Chamber Technology) is a patented core shape that pulls the noise down while keeping the power up — so you can ride where the decibels get measured without giving up performance. Internal ducts in the chambers increase volume and improve flow, so power rises across the whole rev range. Factory Forward Engineering centralises mass, which helps handling and reduces crash damage. The rear end cap opens with four screws — you swap a tuning insert or spark arrestor without taking the silencer off. Works with the stock header or an FMF one. Fits: Yamaha YZ 450 F (2018–2027); Yamaha WR 450 F (2019–2026); Yamaha YZ 450 FX (2019–2023, 2025–2026). Specifications — muffler material: Stainless Steel, Aluminum, end cap material: Carbon Fiber, muffler finish: Natural. Spark arrestor included. QuietCore 94 dB insert included. Delivery 5–8 working days. SKU: 044443.