23-24 YZ450F FACT RCT4.1 FS SS/AL

Incorporates FMF Resonance Chamber Technology™ both internally and externally Shorter overall length that is less susceptible to crash damage and complementary to Factory Forward Engineering, moving the muffler closer to the motor to centralize mass Constructed from only aerospace grade materials that meet exacting specifications and is manufactured 100% at the southern California factory For closed course competition only Spark arrestor screen insert included 94dB insert included