My original engine on this bike was a Mitsubishi TLE 43, very good engine with adequate power and super quite. Of course, as with most members of this forum, adequate just isn't good enough. When I was considering the CY R460, which has twice the power of the TLE43, I was warned that the power came at a price, headache level NOISE. This warning was well founded because it's basically a chain saw engine and sounds like one. I believed I could bring the DB level down to a manageable level and after several trial and error secessions I'm finally happy. At cruise, it's almost as quite as the Mits, although somewhat louder when you get down on the throttle but I can live with that. My secondary muffler is made from 1" copper tubing for the outer jacket with a full length ½" copper straight through baffle tube. The muffler is 11" long with 8" of the baffle tube bored with 48 - 3/16" holes to form a double helix pattern around the tube. The space between the outer jacket and the baffle tube is packed with fiber glass and the muffler can be repacked. I connected the secondary muffler to the primary with silicone tubing and so far it's working great. DDM was my supplier for the engine and the silicone exhaust tubing. They also have secondary mufflers that may work as well or better than mine at a reasonable price. Maybe it's just getting old, but for me, a quite ride beats a loud ride. In the end I'll take either one.