R-77 Slip-On Exhaust. The popular R-77 offers outstanding performance, thanks to being developed in the heat of competition. It features a trapezoidal design, which allows a large volume of packing material and in turn delivers top performance. The R-77 muffler's front cap is MIG-welded, while the end cap is riveted using high-end 304-L polished stainless steel rivets and bands. Superbike technology and styling. Trapezoidal-shaped sleeve. Large volume of packing material. Straight baffle for ample flow. Innovative end-cap. Removable low-volume insert.