The unique attributes of the DR.D*s step system is that it allows for a more efficient intake stroke. It does this by resisting the reflective exhaust pulse during the intake/exhaust overlap. In plain language, the carefully tuned steps in the system allow for a lower net cylinder pressure, which gives a crisper throttle response from bottom to top. The key advantage of the Step System is improved low end response with substantial gain in the mid and top ranges. Dyno tests show a 3.6 horsepower increase at peak. Every DR.D Step System exhaust is manufactured from high-quality, 304-series stainless steel. Each step in the exhaust pipe is achieved via a precision machined ring that not only adds to the performance, but gives the DR.D pipe a distinctive look. The complete system is purged and welded in one of the nation*s best manufacturing facilities. The muffler is constructed out of 6063 aluminum to lower the overall weight of the system and provide an aggressive, but pleasant, exhaust note. DR.D used a *pillow* exhaust packing method to guarantee U.S.F.S. spark arrestor to allow you to use your ATV in a wide range of locales.

Fitment
Yamaha YFZ450 2004
Yamaha YFZ450 2005
Yamaha YFZ450 2006
Yamaha YFZ450 2007
Yamaha YFZ450 2008
Yamaha YFZ450 2009
Yamaha YFZ450 2012
Yamaha YFZ450 2013