Head Pipe Yfz450The 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