Mk45 TOURING MUFFLER for M8 TOURING MODELS—Chrome with Chrome Thruster End Cap

Sounds really deep with a throaty idle. No decal pop to speak of super happy with this slip on!

In February, I bought a 2017 Road King with the new Milwaukee 8 107 Engine. I took a few months to read up on exhausts for the new MOCO build and saw where at least 4 out of the 5 leading builders offered 4.5 inch exhaust designs to compliment. Because HD R&D had opted to go with a 4.5 inch design for the new engine, I decided to stay the course. I had already decided not to run the SE Street Canons, because I was looking for a stronger exhaust note. Several builders offered stepped designs with 2.5 inch baffles opening up into larger diameter reversion chambers at the end. As a starting point, I decided on a design like this from a notable and reputable builder. It was a fine quality build, finished in perfection. After tuning the engine twice, (2nd time after about 1000 miles), although the note was pronounced and deep with the engine running smooth through all gear transitions and seeming to make good gains in the higher rpms, I found the throttle response to be lacking, particularly in pull offs and at higher speeds rolling on for immediate speed. I decided to swap out and try the S&S MK 45’s. The S&S 4.5 Inch mufflers have a full length 2.5 inch baffle and offer an optional 2 inch baffle insert called a DB killer, which simply slides into the baffle and screws into the muffler end cap. Out of the box, the mufflers were packaged well, immaculately built, and so was the fit. The clamps included with the mufflers were obviously a better upgrade from the usual clamps found at the dealerships. The mounting design under the hard bags was great too. I installed the mufflers in about 15 to 20 minutes and headed out to record tuning files. My engine response was immediate and responsive. On every throttle pull, the front end immediately lifted in the suspension. When I headed out onto the 4 lane and cranked it, the M8 snapped into action with instantaneous power gains and rapid acceleration. The sound is a “make no mistake about this” kind of dominant exhaust note. With every snap of the throttle, the pipes sound off and the engine delivers the goods. The MK 45’s are true performers. Also, just like the SE Street Canons (and unlike some of the other builders), the MK 45’s have different design end caps that can be swapped out and changed. Considering the included “DB killers” (an accessory which no doubt would even add more back pressure) and the S&S design/build quality, the MK 45’s are versatile and offer the best bang for the buck. In terms of Design, Build, and Performance, S&S pegged it on the Mark 45’s for the Milwaukee 8 107.

These slip ons look great and sound about as good as you can expect from a slip on. Installation was super easy...20 minutes including unpacking them!

Traded my 2009 Road King Classic with Rinehart slip-on pipes. Now ride a 2017 Road King. Just got S&S slip-ons for replacement of my stock exhaust. Great sound with baffles. Have not tried it with the baffles out. Good enough for me for now as is.