So you decided to pick up a new touring model from Harley this year with the new Milwaukee-Eight. The bike has a ton of style and features that no other motorcycle has. Except for one thing. The motorcycle's exhaust is whisper quiet and doesn't have any of the rumble you'd expect coming out of a machine like that.
You mentioned the fact the bike is so quiet to the the salesman at the Harley dealership, and that you wanted an exhaust that sounds good and adds some performance too. The salesman shows you the The Screamin’ Eagle High-Flow Exhaust system, manufactured with Harley's name on it. At $1400 to $1500, it must be a great system! He or she may even have started up a bike with the same system on it inside the shop and it sounded loud and deep.
As you begin riding your new bike, you start to notice it doesn't have the nice rich tones and real hot rod sound of almost any of the aftermarket choices you hear and see on many of the baggers you've encountered in your travels.
You start exploring aftermarket slip on muffler choices like the TAB Performance BAM Sticks, SVT Jackhammers, or Cobra Neighbor Hater mufflers. The sound clips you're hearing online from West End Videos and other sources convince you you want more from your exhaust system and you pull the trigger and order a set of mufflers guaranteed to get your M-8 bagger sounding awesome.
The only problem is when you try to install them, the slip on mufflers will not fit the Screamin' Eagle header. So what's going on with Harley's Screamin' Eagle High Flow Exhaust System? Let's take a look at their system and break it down.
The system looks like many of the aftermarket performance system except for two standouts. Number one is that they moved the catalytic converters to the mufflers from the head pipe. But more importantly is number two, the Large Diameter Muffler Inlets are 2.25" and are a unique size to this system. The important thing to know is that the Screamin' Eagle High Flow Exhaust is that it's sold as a complete system and doesn't have replacement mufflers available to swap out. Harley does this to keep you EPA compliant by not allowing you to remove the catalytic converters.
If you want to use a great sounding set of mufflers and lose the heat of the catalytic converters melting your saddlebags, you need to install a performance header. The original stock muffler inlet sizes are 1 3/4" on the left and 2 1/2" on the right to accommodate the extra heat from the cat. With only a couple of exceptions, all 2017-Up aftermarket mufflers and head pipes are built to the stock size.
If you have Harley's Screamin' Eagle High Flow Exhaust System and you want a change, pick out a set of mufflers you like and shop for headers.