FMF Racing Yamaha YFZ450 04-09/12-15 Q4 S/A Muffler

A 4-Stroke header system that incorporates FMF's patented Power Bomb module at a precise location in the initial stage of the header system; by positioning the "Bomb" at this key point, the expansion and contraction of exhaust sonics through the system resulting in a flow increase of nearly 10%. The surface of the perforated core lets the sound exit into the absorbing material (steel wool packing) and then allows the air to expand, cool and ramp back up at higher air pressures (RPMs). The Power Bomb is a "pre-muffler" of sorts, which helps to lower the bike's sound output because it provides more sound-absorbing surface area to allow the exhaust gases to become absorbed. Fitment: 2004 Yamaha YFZ450 Base 2005 Yamaha YFZ450 Base 2006 Yamaha YFZ450 Base 2007 Yamaha YFZ450 Base 2008 Yamaha YFZ450 Base 2009 Yamaha YFZ450 Base 2012 Yamaha YFZ450 Base 2013 Yamaha YFZ450 Base 2014 Yamaha YFZ450 Base 2015 Yamaha YFZ450 Base