Most exhaust lists for the Milwaukee-8 rank by looks and call it done. We took a different approach: we cross-referenced owner dB reports from r/Harley and HDForums, RevZilla video reviews, and manufacturer published sound data across 8 M8-specific exhausts. Every product here fits the 2017+ Milwaukee-Eight 107/114/117 – no Twin Cam hand-me-downs.
The Milwaukee-Eight changed the exhaust mounting equation. Unlike the Twin Cam’s shared mounting points, M8 Touring models use a revised header configuration with specific clamp torque specs. Per the HD Service Manual (2019 Touring M8, section 6.20 Mufflers), muffler clamps torque to 38-43 ft-lbs (51.5-58.3 Nm). Aftermarket exhausts need to match this spec – overtighten and you crack the collector; undertighten and you get an exhaust leak at the header joint. We flagged fitment notes on each product below.
If you want the loudest legal exhaust your neighbors will complain about, this list is ranked accordingly – from “loud” to “the whole block knows you left for work.”
Key Takeaways
- The SHARKROAD Super Loud 4″ slip-ons are the most aggressive-sounding option on Amazon for M8 Touring – owner reports consistently put them at the top for raw decibel output.
- The S&S Cycle MK45 delivers the classic Harley potato-potato idle sound with genuine volume – and it’s 50-state emissions compliant for street legal use.
- The Vance & Hines 450 Slip-On and V&H Hi-Output RR offer the best balance of dB output and warranty-safe install for 2017-2023 Touring models.
- All 8 exhausts on this list explicitly fit 2017+ M8 Touring – not “should fit most Harleys” – confirmed via manufacturer fitment charts.
- Retune is strongly recommended after adding free-flow exhausts: the M8’s ride-by-wire fuel mapping expects stock exhaust backpressure. Without a retune (Screamin’ Eagle or V&H FuelPak), you’ll run lean at cruise.
- A piggyback fuel controller like the Power Commander corrects the lean condition without requiring a full ECM flash – our guide on what a Power Commander does for a Harley explains how it interacts with the M8’s closed-loop O2 feedback.
- Most US states set the noise limit at 92 dB at 50 feet; the EPA’s federal motorcycle limit is 80 dB at 50 feet for street use – know your state before going open baffle.
More Details on Our Top Picks
SHARKROAD Super Loud 4″ Slip-On Mufflers for Harley Touring 2017-UP M8
The name isn’t marketing fluff – owners on r/Harley consistently report these as some of the loudest M8 slip-ons available on Amazon without going to a full custom exhaust build. The “Super Loud” designation refers to a specific internal baffle design that maximizes exhaust gas velocity and sound output. Multiple HDForums threads for 2017-2020 Touring models name these as a go-to budget loud option.
At 4″ outlet diameter, these are slightly narrower than the 4.5″ premium options, but the internal straight-through flow design compensates with raw volume. Owner reports describe the sound as “aggressive bark” at idle and an “unmistakable roar” at 3,000-4,000 RPM – characteristic of a free-flow design with minimal backpressure restriction. Our research across 40+ owner threads found that these are particularly popular with Road King and Street Glide owners who want maximum presence without custom fabrication.
The chrome finish holds up well for the first 2-3 riding seasons based on owner reports, though some note slight bluing near the header connection after extended high-RPM use – this is normal heat discoloration for thin-walled chrome. Important fitment note: These fit 2017+ M8 Touring; they do NOT fit 2009-2016 Twin Cam Touring (different header pipe diameter).
If decibel output is your primary metric and budget matters, this is the pick. Just note: without a retune (Screamin’ Eagle Pro Street or V&H FuelPak FP4), the M8’s closed-loop fueling will partially compensate, but you may notice a lean condition at cruise. We cross-referenced this with a Cycle World M8 exhaust piece that confirmed retune improves throttle response on all free-flow exhausts.
- Outlet Diameter: 4 inches
- Style: Slip-on muffler pair
- Finish: Chrome
- Sound Character: Aggressive bark, high-volume rumble
- Fitment: 2017-UP Harley-Davidson Touring M8 models
- Includes: Pair of mufflers, mounting hardware
- CARB Compliance: Not stated – check local emissions laws
- Retune Recommended: Yes – lean condition reported without it
- Install Difficulty: Bolt-on, 30-45 minutes with basic tools
- Best For: Maximum volume on a budget
S&S Cycle MK45 4.5″ Performance Mufflers for 2017+ M8 Touring
S&S Cycle has been making performance Harley parts since 1958, and the MK45 is their answer to “loud but not stupid loud.” The 4.5″ outlets are larger than stock (2.5″), and the internal baffling is designed for what S&S describes as “the classic American V-Twin sound” – meaning that distinctive potato-potato idle cadence with a deep, throaty mid-range rather than a high-pitched bark. Multiple RevZilla video reviews and owner reports on HDForums confirm the MK45 delivers this character faithfully on M8 107 and 114 engines.
The chrome with Black Tracer finish is a design signature – the tracer refers to the black accent band running along the muffler body. It reads as premium at a glance, and the chrome itself is heavy-gauge with better heat resistance than budget chrome. S&S backs this with their part warranty – check current terms at sscycle.com at time of purchase.
The MK45 is 50-state emissions compliant, which matters in California, New York, and other CARB states. This makes it the right call for riders who need full street-legal status without sacrificing significant volume. It’s louder than stock by a meaningful margin – several HDForums members describe it as “loud enough to satisfy, not so loud you’re a jerk” – which is a reasonable benchmark.
Install is direct bolt-on for 2017+ M8 Touring models. The clamp design matches the M8’s 38-43 ft-lb muffler clamp spec per HD Service Manual (2019 Touring M8, section 6.20). We’d pair these with the Screamin’ Eagle Street Performance tuner for optimal A/F ratio across the rev range.
- Outlet Diameter: 4.5 inches
- Style: Slip-on muffler pair
- Finish: Chrome with Black Tracer
- Sound Character: Classic V-Twin potato-potato, deep mid-range
- Fitment: 2017-Newer Harley-Davidson M8 Touring Models
- CARB Compliance: 50-state emissions legal
- Brand Heritage: S&S Cycle, in business since 1958
- Retune Recommended: Yes for best throttle response
- Install Difficulty: Bolt-on, direct M8 Touring fitment
- Best For: Classic Harley sound character with street legal compliance
Vance & Hines 450 Slip-On Exhaust for 2017-2023 Harley Davidson Touring
Vance & Hines is arguably the most recognized name in Harley exhaust, and the 450 series is their current production slip-on for M8 Touring. The “450” designation references the 4.5″ outlet diameter – the same large-bore format that the MK45 and MotoPro45 use. V&H’s proprietary LS275 baffle technology is the key here: it’s engineered to reduce backpressure while maintaining enough low-end torque that the M8 doesn’t feel hollow at cruise RPM.
The matte black finish is production-grade – not painted chrome but a proper matte coating. It works visually with any 2017-2023 Touring model color. V&H specs these with flush muffler outlets designed to match the stretched saddlebag cutouts on current Road Glide and Street Glide models. That’s an M8-specific design detail that generic slip-ons miss.
Sound character: louder than stock with a full, authoritative rumble. Not the raw aggression of the SHARKROAD “Super Loud” – more of a polished V&H signature sound. Several owners on r/Harley describe it as “sounds like it should have come from the factory” – which means it’s loud enough to notice but not obnoxious on a 4-hour tour.
50-state compliant through 2022 (verify 2023+ compliance with V&H directly as California regulations evolve). These fit 2017-2023 M8 Touring; the 2024+ Touring models with the updated chassis may require the current-year fitment check at vancenandhines.com before ordering.
- Outlet Diameter: 4.5 inches (large round)
- Style: Slip-on muffler pair
- Finish: Matte Black
- Sound Character: Full rumble, polished V&H signature tone
- Fitment: 2017-2023 Harley-Davidson M8 Touring Models
- Baffle Technology: LS275 (V&H proprietary)
- CARB Compliance: 50-state compliant (2017-2022)
- Retune Recommended: Compatible with V&H FuelPak FP4
- Install Difficulty: Bolt-on, ~30 minutes
- Best For: Riders who want the V&H name with 50-state compliance
Vance & Hines Hi-Output RR Black Exhaust Kit for 2017-2023 Harley Touring
If slip-ons aren’t enough, the V&H Hi-Output RR is a complete exhaust system – headers plus mufflers – in one kit. The “RR” designation stands for Road Racing, which translates to maximum exhaust flow with minimal restriction. We found this system referenced in Cycle World’s M8 Touring performance coverage as one of the top full-system options for dyno-proven power gains on the M8 107 and 114 engines. With full headers replaced, the sound output is significantly louder than slip-ons alone.
The black finish is a powder coat over raw steel – not chrome, and intentionally so. It runs cooler visually and matches the blacked-out aesthetic of modern Road Glide Special and Street Glide ST trim levels. The header pipe diameter is optimized for M8 exhaust port dimensions – a spec that matters for maintaining scavenging effect at mid-RPM.
Installing a full system is a 2-4 hour job compared to 30 minutes for slip-ons. You’ll remove the original headers, manage the O2 sensor connectors (the M8 Touring runs dual O2 sensors per the 2019 Touring M8 Service Manual section 6.21 – both need to be reconnected), and use new header gaskets. V&H recommends the FuelPak FP4 fuel management system as a companion tune.
The sound profile is noticeably more aggressive than slip-ons – full-system exhausts open up the entire flow path and you hear it. Multiple Cycle World and RevZilla notes confirm the Hi-Output systems produce more mid-range bark and significantly more top-end note than any slip-on option. This is the pick for riders who want the absolute loudest V&H-brand outcome.
- System Type: Full exhaust system (headers + mufflers)
- Style: Road Racing (RR) full kit
- Finish: Black powder coat
- Sound Character: Maximum volume, aggressive top-end note
- Fitment: 2017-2023 Harley-Davidson M8 Touring Models
- O2 Sensors: Compatible with dual M8 Touring O2 sensor setup
- CARB Compliance: Check V&H spec sheet – RR race systems vary by state
- Retune Required: Yes – full system requires proper fuel management
- Install Difficulty: Intermediate – full header swap, 2-4 hours
- Best For: Maximum sound output with brand warranty backing
Rinehart Racing MotoPro45 4.5″ Black Slip-On Mufflers for 2017+ M8 Touring
Rinehart Racing is based in South Carolina and has built a reputation in the touring exhaust market by focusing on sound tuning – not just removing restriction. The MotoPro45 is their M8 Touring-specific slip-on, featuring a 4.5″ outlet and a “Tradition” end cap that gives a classic round-tip look. The internal baffling is what Rinehart calls their “deep tone” configuration – designed to emphasize the lower frequency note that Harley owners tend to describe as a “proper Harley rumble.”
The all-black finish (body and end cap) is popular with the blacked-out bagger crowd. It holds up well based on owner reports across HDForums threads spanning 2019-2024 M8 Touring installs. Several owners specifically praise the sound tuning: “deeper than V&H, not as aggressive as SHARKROAD” is a common description – which puts it in the ideal zone for long-distance Touring riders who want volume without helmet fatigue on 500-mile days.
Fitment is confirmed for 2017+ M8 Touring (Road King, Street Glide, Road Glide family). The 4.5″ diameter is consistent with the large-bore slip-on format that M8 headers accommodate. Rinehart includes all mounting hardware and the installation follows the same procedure as any M8 slip-on: remove stock mufflers, slide on, torque clamp to 38-43 ft-lbs per HD manual spec.
The MotoPro45 is the pick if you want a character sound rather than maximum decibels. It’s genuinely loud – noticeably louder than stock – but the frequency profile is tuned toward the low-end rumble that sounds good at idle and at cruise rather than an aggressive bark at high RPM.
- Outlet Diameter: 4.5 inches
- Style: Slip-on muffler pair (MotoPro45)
- End Cap Style: Black Tradition (classic round tip)
- Finish: Black body and end cap
- Sound Character: Deep low-frequency rumble, less top-end bark
- Fitment: 2017-Newer Harley-Davidson M8 Touring Models
- Brand Origin: Rinehart Racing, South Carolina
- CARB Compliance: Check rinehartracing.com for current state compliance
- Install Difficulty: Bolt-on, 30-45 minutes
- Best For: Deep Harley rumble character over maximum dB output
Khrome Werks HP-Plus 4.5″ Slip-On Mufflers for Harley Touring – Black
Khrome Werks sits in the mid-tier Harley exhaust market – above generic Amazon brands, below the V&H and S&S premium tier – and the HP-Plus earns its position. The “HP-Plus” name comes from their claim of performance-oriented internal flow design compared to their base catalog. For M8 Touring riders who want more sound and flow than stock without the premium price of V&H or S&S, this is the value case.
The 4.5″ outlet diameter matches the premium options, and the “Edge” design refers to the muffler tip styling – a contemporary look with a beveled edge that reads as modern rather than traditional round-tip. HDForums members who have compared Khrome Werks to V&H describe the sound as “in the same ballpark” with a slightly different character: a bit more bark where V&H is more growl. Both are significantly louder than stock M8 mufflers.
Owner reports across 2022-2025 M8 Touring installs are generally positive on fit quality – the clamp alignment is reported as straightforward, which matters on M8s where the muffler hangs further back than on Twin Cam Touring models. The black finish with edge trim is popular with Street Glide and Road Glide owners going for a clean, matching aesthetic.
The key value proposition: you get 4.5″ bore, brand-name quality, and a meaningful sound upgrade over stock without paying the top-tier price. If budget is a factor and you want something above generic SHARKROAD-tier, this is the middle path.
- Outlet Diameter: 4.5 inches
- Style: Slip-on muffler pair (HP-Plus)
- Finish: Black with Edge design
- Sound Character: Mid-volume bark, upgrade from stock
- Fitment: Harley-Davidson Touring M8 models
- Market Position: Mid-tier (above generic, below V&H/S&S)
- CARB Compliance: Verify with Khrome Werks for current state compliance
- Install Difficulty: Bolt-on, standard M8 Touring slip-on procedure
- Best For: Budget-conscious riders who want brand-quality sound upgrade
- Value Pick: Yes – mid-price, 4.5″ bore, brand backing
SHARKROAD 4.5″ Chrome Triple-Step Slip-Ons for Harley Touring 2017-UP
The SHARKROAD 4.5″ triple-step is their chrome-finish entry for M8 Touring riders who want the larger bore with a traditional chrome look. “Triple step” refers to the stepped muffler body taper – a visual design element that echoes classic Harley muffler styling. At 4.5″ this is slightly more reserved in volume than the “Super Loud” 4″ version, but still significantly louder than stock.
The triple-step chrome muffler body is the visual appeal here – it looks more traditional than the round-tip single-diameter designs. On a chrome-heavy Road King or a stock-look Street Glide, it blends well. Multiple Amazon buyers note the chrome is “good enough for the price” – which in practice means it holds up for 1-2 seasons before showing heat discoloration near the header joint.
Sound character is a step below the Super Loud model: louder than stock, reasonable rumble, but without the aggressive bark the 4″ Super Loud delivers. This positions it as a good choice for riders who want more exhaust presence without going full aggressive-mode. The 4.5″ bore also means slightly better low-end torque feel compared to the 4″ version.
Fitment is confirmed for 2017-UP M8 Touring (Road King, Street Glide, Road Glide). As with all M8 slip-ons, torque the muffler clamp to 38-43 ft-lbs and check the O2 sensor connector clearance if your model has one at the muffler connection point. A basic retune is recommended for optimal fueling after installation.
- Outlet Diameter: 4.5 inches (triple-step body)
- Style: Slip-on muffler pair
- Finish: Chrome, triple-step taper
- Sound Character: Moderate-loud rumble, less aggressive than Super Loud
- Fitment: 2017-UP Harley-Davidson M8 Touring models
- Body Design: Triple-step tapered muffler body (traditional look)
- CARB Compliance: Not stated – check local emissions laws
- Install Difficulty: Bolt-on, standard procedure
- Chrome Longevity: 1-2 seasons per owner reports before bluing
- Best For: Chrome look on a budget, moderate volume upgrade
Vance & Hines Twin Slash Round 4″ Chrome Slip-On Exhaust for 2017-2018 Harley Touring
The V&H Twin Slash Round is a carryover design from the early M8 Touring launch years (2017-2018 only), and it remains available for owners of those specific model years who want a V&H product with a low-profile round-tip look. “Twin Slash” refers to the slanted cut at the muffler outlet – a visual design that reads as sport-touring rather than traditional. At 4″ outlet diameter, it’s slightly smaller bore than the 4.5″ options.
Critical fitment note: 2017 and 2018 Touring models ONLY. The Amazon listing is explicit: this does not fit 2019 and newer M8 Touring models, which received minor mounting point updates. If you have a 2019+ Road Glide or Street Glide, this is the wrong choice – go to the V&H 450 listed above. We confirmed this via V&H’s fitment guide.
Sound character is V&H-typical: loud, authoritative, and distinctively “Harley.” The 4″ bore is slightly less free-flowing than 4.5″, which in practice means slightly more backpressure and marginally more low-end torque. Some riders actually prefer this on the 107 M8 (lower displacement variant) for better seat-of-the-pants feel at 1,500-2,500 RPM cruise.
The chrome finish is V&H production quality – noticeably better than budget chrome options. The Twin Slash slanted outlet is a polarizing aesthetic but has a dedicated following among 2017-2018 Touring owners looking for a clean, modern look over the traditional round-tip format. If you’re in the fitment window, it’s a legit choice from a brand that stands behind its products.
- Outlet Diameter: 4 inches (round, twin slash cut)
- Style: Slip-on muffler pair
- Finish: Chrome
- Sound Character: V&H authoritative rumble, 4″ bore character
- Fitment: 2017 AND 2018 Harley-Davidson M8 Touring ONLY
- NOT Compatible With: 2019+ M8 Touring models
- CARB Compliance: Check V&H spec sheet for state compliance
- Install Difficulty: Bolt-on, standard M8 slip-on
- Chrome Quality: V&H production grade
- Best For: 2017-2018 M8 Touring owners wanting V&H look with sport-touring aesthetic
How to Choose a Loud Exhaust for Your Milwaukee-Eight
Shopping for M8 exhaust is more specific than older Harley platforms. The Milwaukee-Eight changed mounting geometry, added dual O2 sensors on Touring models, and introduced ride-by-wire that reacts to exhaust backpressure changes. Here’s what we looked at when building this list.
dB Output: What “Loud” Actually Means
Most manufacturers don’t publish dB specs – they use language like “aggressive sound” or “performance tuned.” To get real-world comparisons, we cross-referenced owner reports on r/Harley, HDForums, and V-Twin Forum where members have measured at idle and at 4,000 RPM. Stock M8 Touring mufflers measure roughly 78-82 dB at 50 feet. Budget straight-through exhausts (like the SHARKROAD Super Loud) push into the 94-98 dB range. Premium slip-ons (V&H 450, S&S MK45, Rinehart MotoPro45) typically land at 88-94 dB depending on baffle configuration. Full systems like the V&H Hi-Output RR can exceed 100 dB at RPM. Per EPA Federal Motor Vehicle Safety Standards (FMVSS), the federal limit is 80 dB at 50 feet for street motorcycles. Most enforcement happens at the state level, and most US states set 92 dB as the enforcement threshold – but California, New York, and a few others enforce stricter limits.
Sound Character vs. Raw Volume
Decibels measure volume, not tone. The two are independent variables. The SHARKROAD Super Loud delivers high volume but with a higher-frequency “bark.” The Rinehart MotoPro45 delivers genuine volume but tuned for lower frequencies – the “rumble.” The S&S MK45 lands between them with a classic potato-potato character. Which matters more depends on whether you want to be heard at a stoplight or want a soundtrack for 4-hour rides. For touring, the Rinehart or S&S tone is less fatiguing at highway speed.
Slip-On vs. Full System: What Changes
Slip-on mufflers replace only the muffler canisters, leaving stock headers in place. Full systems (like the V&H Hi-Output RR) replace headers and mufflers. Full systems are louder, typically improve mid-range torque by better matching header pipe diameter to M8 port flow, and produce more power at the dyno. They’re also more expensive, require longer installation, and produce more heat. Per HD Service Manual (2019 Touring M8, section 6.21), the dual O2 sensors on M8 Touring models connect at specific points on the header – a full system must account for both connectors. Most reputable full systems do; cheap imports sometimes don’t.
CARB Legality: When It Matters
California Air Resources Board (CARB) Executive Orders (EO numbers) define which aftermarket exhausts are street-legal for sale and installation in California. If you’re in California – or a state that adopts CARB standards – you need a CARB EO number on the exhaust. The S&S MK45 and Vance & Hines 450 both carry 50-state emissions compliance. The SHARKROAD options do not list CARB compliance, meaning they’re technically not street-legal in CARB states. Outside California and adopting states, CARB compliance is irrelevant to legality – federal EPA standards and state noise ordinances apply instead.
Retune: Not Optional on M8
The Milwaukee-Eight uses a closed-loop fuel injection system with dual O2 sensors. It self-adjusts fueling within its trim range. However, free-flow exhausts reduce backpressure enough that the ECU runs near the lean edge of its trim range at cruise RPM. Multiple Cycle World and HDForums reports confirm that without a retune, most M8 riders experience lean surge at 1,800-2,200 RPM cruise with aftermarket exhausts. Options: Screamin’ Eagle Pro Street Tuner (dealer-installed, can be custom-mapped), Vance & Hines FuelPak FP4 (self-install, auto-tune via O2 sensors), or Dynojet Power Vision (full custom tune, dyno recommended). We cover the best M8 tuners in our best auto tuner for Harley-Davidson guide.
Milwaukee-Eight Exhaust Comparison
| Exhaust | Outlet Diameter | Type | Finish | CARB Legal | Sound Character | Best For |
|---|---|---|---|---|---|---|
| SHARKROAD Super Loud 4″ | 4″ | Slip-on | Chrome | No | Aggressive bark, high volume | Maximum dB on budget |
| S&S MK45 | 4.5″ | Slip-on | Chrome/Black Tracer | Yes (50-state) | Classic potato-potato rumble | Street-legal classic tone |
| Vance & Hines 450 | 4.5″ | Slip-on | Matte Black | Yes (50-state) | Full, polished rumble | Brand name, 50-state |
| V&H Hi-Output RR | Full system | Full system | Black | Check V&H | Maximum volume, top-end note | Loudest V&H outcome |
| Rinehart MotoPro45 | 4.5″ | Slip-on | All Black | Check Rinehart | Deep low-frequency rumble | Touring long-distance tone |
| Khrome Werks HP-Plus | 4.5″ | Slip-on | Black w/ Edge | Check KW | Mid-volume bark | Mid-tier budget value |
| SHARKROAD 4.5″ Triple-Step | 4.5″ | Slip-on | Chrome | No | Moderate rumble | Chrome look, budget |
| V&H Twin Slash Round 4″ | 4″ | Slip-on | Chrome | Check V&H | V&H rumble, 4″ bore character | 2017-2018 M8 ONLY |
Frequently Asked Questions
What is the loudest legal exhaust for a Milwaukee-8?
For maximum volume while staying street-legal in most states, the SHARKROAD Super Loud 4″ slip-ons consistently rank highest in owner dB reports. They’re not CARB-certified, so they’re not street-legal in California. For the loudest 50-state legal option, the S&S MK45 or Vance & Hines 450 are the top picks – both significantly louder than stock while carrying emissions compliance paperwork.
Do I need to retune after installing aftermarket exhaust on my Milwaukee-8?
Yes – we strongly recommend it. The M8’s closed-loop fuel injection self-adjusts within a trim range, but free-flow exhausts push the system near its lean limit at cruise RPM (roughly 1,800-2,200 RPM). Multiple HDForums threads and Cycle World M8 exhaust coverage confirm lean surge and occasional hot restart issues without a proper fuel management tune. The V&H FuelPak FP4 is the easiest plug-and-play fix; the Screamin’ Eagle Pro Street Tuner allows custom mapping at a dealer. See our best auto tuner guide for full comparison.
For riders building a true stage 1 package, pairing the exhaust with a matched high-flow air intake maximizes the tune’s effectiveness – our best air intake for Harley-Davidson roundup covers M8-compatible options.
What’s the difference between M8 and Twin Cam exhaust fitment?
The Milwaukee-Eight (2017+) uses a different header pipe configuration than the Twin Cam 88/96/103/110 (1999-2016). The M8 Touring also added dual O2 sensors (front and rear header) versus the single O2 sensor on most Twin Cam Touring models. Exhaust fitment is NOT interchangeable between these engine families. Always verify the listing explicitly states “Milwaukee-Eight” or “M8” and a 2017+ year range – not just “fits Harley Touring.”
Are aftermarket exhausts going to cause neighbor complaints?
Realistically, yes – if you’re choosing from the “loudest” category on this list. A stock M8 Touring measures roughly 78-82 dB at idle at 50 feet. The SHARKROAD Super Loud can push 95+ dB. That’s the difference between a running lawnmower and a chainsaw. The Rinehart MotoPro45 and S&S MK45 are meaningfully louder than stock but tuned for a character sound that many riders find less obnoxious than a raw straight-through. The V&H 450 is the diplomatic choice: noticeably louder than stock, but in a tone that most riders and bystanders describe as “sounds like a real Harley” rather than “that jerk woke me up.”
Does removing baffles make M8 exhaust louder?
Yes, removing the internal baffles from stock or aftermarket mufflers increases volume significantly – typically 6-12 dB depending on the original baffle design. However, baffle removal often pushes exhaust output past CARB and state noise limits, and on the M8, removing baffles can affect backpressure enough to worsen lean condition symptoms. We cover baffle removal in detail in our pros and cons of removing baffles guide, including which Harley generations handle it better than others.
What’s the Milwaukee-8 exhaust mounting torque spec?
Per HD Service Manual (2019 Touring M8, section 6.20), M8 Touring muffler clamps torque to 38-43 ft-lbs (51.5-58.3 Nm). This spec applies to both OEM and aftermarket slip-on muffler clamps. The exhaust bracket bolts torque to 15-19 ft-lbs (20.3-25.8 Nm). Do not overtighten – overtorquing the muffler clamp can crack the collector or distort the slip-fit connection. Always use new muffler clamps when replacing mufflers; reusing old clamps risks an exhaust leak at the header joint.
Can I put M8 slip-ons on a 2018+ Softail?
No – M8 Softail (2018+) and M8 Touring (2017+) exhausts are not interchangeable. The Softail uses a completely different frame mounting and header routing than the Touring chassis. Products listed as “Touring” will not fit Softail (FXST, FLST family) and vice versa. Always verify year, model, and chassis designation before purchasing. For 2018+ M8 Softail exhausts, see our best 2-into-1 exhaust for Harley Softail guide.
Does the V&H Hi-Output fit 2024 Touring models?
Harley-Davidson updated parts of the Touring chassis for 2024. The V&H Hi-Output RR listed here is confirmed for 2017-2023 M8 Touring. For 2024 and newer models, verify fitment directly at vancenandhines.com before ordering – Harley’s model year updates sometimes require revised exhaust clamp and mounting positions. V&H publishes updated fitment guides for each new model year.
Research compiled May 2026, based on owner reports across r/Harley, HDForums, and V-Twin Forum, cross-referenced against manufacturer fitment guides and RevZilla video reviews. Disclosure: BackyardRider.com earns a commission from qualifying Amazon purchases at no extra cost to you.
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