Loud M8 Touring Mufflers for Harley Davidson Models

Key Takeaways

• Milwaukee-Eight Touring models use four valves per cylinder, and their exhaust note differs from earlier Twin Cam and Evolution-powered bikes.
• Slip-on muffler volume depends on baffle design, muffler construction, head pipes, catalyst configuration, and the rest of the engine setup.
• A louder muffler does not automatically make more power. Exhaust-gas velocity, scavenging, and pressure-wave timing matter more than simply adding backpressure.
• Current options from brands such as TAB Performance and Penn Steel Works let riders choose among different sound levels without replacing the complete exhaust system.

I’m sure the first thing you noticed about your new M-8 Harley Davidson touring model is that the exhaust is very quiet. Many would say too quiet for a motorcycle that has been setting the standard of what an iconic engine sounds like. Stock motorcycles are designed to meet applicable emissions and sound requirements, so the factory exhaust has a different goal than a high-volume aftermarket muffler.

If you have previously owned a Harley Davidson touring model, it was easy to achieve the throaty Harley growl and roar on a Twin-Cam or an Evo. But the Milwaukee-Eight inherently has a different tone altogether due to the head and valve configuration and other changes to the engine and exhaust system. The Milwaukee-Eight uses four valves per cylinder, compared with two valves per cylinder on the Twin Cam.

The catalytic converter and other parts of the stock exhaust system also affect exhaust tone, flow, and heat. If you plan to change the headers or other emissions-related components, check the product’s approved application and the requirements that apply to your motorcycle before making the change.

How Baffle Design Changes M8 Exhaust Sound

In the meantime, what can be done to get better sound? A few manufacturers have designed baffles in their mufflers to give you the most you can get from the stock headers. Baffle diameter, core design, packing, muffler-body size, and outlet design can all change the volume and depth of an M8 Touring exhaust. A larger or more open core is often louder, but baffle size alone does not determine how a muffler will sound.

There is a tradeoff between sound and exhaust tuning, but “louder” and “more power” are not the same thing.

The Milwaukee-Eight does not simply need more backpressure to make torque. Pipe diameter, length, collector design, baffles, exhaust-gas velocity, and pressure-wave timing all affect how the system performs across the RPM range.

After installing aftermarket slip-on mufflers, you will notice a big change in sound, but the performance change can be much smaller on an otherwise stock motorcycle. Slip-ons primarily change the final section of the exhaust system, and results vary by product and engine setup.

If you also install a high-flow air cleaner kit, check the intake and exhaust manufacturers’ recommendations for fuel calibration. Tuning requirements depend on the combination of parts and the motorcycle’s existing calibration rather than a universal requirement to have every bike flash-tuned by a Harley Davidson dealer.

Choosing a High-Volume M8 Touring Muffler

If you want more sound while retaining the stock headers, high-volume slip-ons give you several choices. Some manufacturers also offer removable or selectable baffles, allowing you to change the exhaust note without replacing the complete muffler.

If you later decide to change the fuel-management system or head pipes, choose components intended for your exact application. Federal law prohibits tampering with required emissions controls on EPA-certified vehicles, and individual exhaust products may also have separate emissions and noise-use restrictions.

For example, TAB Performance] offers 4.5-inch BAM Sticks and other M8 Touring mufflers with selectable baffle options, including the Zombie baffle on compatible products.

Penn Steel Works Rebellion slip-on mufflers use interchangeable Mellow, Mild, and Wild inserts, giving riders three sound levels from one muffler set.

Shop M8 Touring Slip-On Mufflers

Call 570-992-1113 if you have any questions about getting a set of aftermarket slip-on mufflers for your Harley Davidson.

Shop all 2017-26 Harley Davidson Touring exhaust options at West End Motorsports. If you are unsure which muffler or baffle setup fits your bike, call and place your order with a West End Motorsports representative for guaranteed fitment.