The Factory 4.1 system was derived from our successful Factory. We developed a completely new system with an ALL NEW muffler design. The Factory 4.1 oval muffler is constructed from military grade titanium utilizing an angle cut end cap and offered in either a natural or anodized blue finish. The performance characteristics start with a formed tapered inlet leading into the muffler. The oval shape combined with the tapered inlet allows the muffler to be routed further forward without interfering with the frame, subframe, shock, rear wheel or brake. Our Factory Forward Engineering lowers and centralizes the machines center of gravity for improved handling without sacrificing silencer volume and durability. With its new formed end cap, the muffler is less susceptible to damage. Complimenting the muffler is our patented PowerBomb titanium header and titanium mid pipe for reducing weight and superior strength. Big-bore 450cc and up motors get the new Factory Forward PowerBomb header to further centralize the weight with the optimum tuned length. The modular exhaust port flange transmits less vibration reducing tension on the system. The all new angle cut end cap offers versatility and tunability with the optional Power Rings and Rev Tubes to alter power delivery. There is also a removable spark arrestor module for off-road applications.