The 2026 Yamaha YZ450F has seen some changes to its engine character. With a new muffler that is a 109db system that all manufacturers will have to adhere to. Yamaha also changed the port sizes in their head and put a resonance chamber inside the air intake to help with sound regulations incoming. With all … Continue reading FMF 4.1 RCT Muffler System For 2026 Yamaha YZ450F