VIDEO: FMF S/S Aluminum Factory 4.1 Muffler System Review - DR Tested

Kris Keefer reviews the FMF Racing S/S Aluminum Factory 4.1 Muffler System for the 2016 Yamaha YZ450F motocross bike.

The 2016 YZ450F was Dirt Rider's open class motocross shootout winner, but that doesn't mean it can't benefit from a little engine massaging. Kris Keefer decided to to try an FMF S/S Aluminum 4.1 muffler system to see if it improved the already potent engine package the Yamaha has to offer. FMF's aluminum 4.1 version still incorporates a carbon fiber end cap and comes with a spark arrestor screen for all you off-roaders out there. The complete system system will cost you $799.99 and is made right here in the good ol' USA!