Your ride back
The all-new 2027 Harley-Davidson Sprint™ 440 brings a different energy to the Harley-Davidson line-up. Lightweight, agile and designed for everyday enjoyment, it makes room for riding in the middle of everything else. The morning commute. A quick trip across town. The longer route home that somehow becomes your favourite part of the day.
With the BOLT exhaust by Dr. Jekill & Mr. Hyde, those moments get their own sound. Switch between three sound modes at the push of a button, from a restrained departure to a fuller, more expressive ride. Always street legal in every mode. A new motorcycle is the beginning. Making it yours is where the fun starts.
Designed around the Sprint
On a compact motorcycle, every detail counts. The length of the body. The way the finish works with the rest of the bike. Our approach brings those details together in an exhaust that complements the Sprint’s proportions and gives it a distinctive finishing touch. Carefully considered mounting, premium materials and a clean silhouette make the exhaust part of the complete motorcycle. Something you notice before you even press the button.
Three sound modes. We know which one's your favourite..
Leave your street quietly. Settle into a balanced tone through town. Select a richer sound as the buildings give way to open roads. One motorcycle, with more ways to enjoy every ride.
Dr. Jekill Mode
With the valve closed, enjoy a more restrained exhaust note. For quiet streets, early departures and arriving home after everyone else has called it a night.
Dynamic Mode
A partially open valve gives your ride a balanced, expressive tone. Enough presence to enjoy the sound, with the refinement you want for everyday riding.
Mr. Hyde Mode
Select the open-valve setting for a fuller exhaust note and a more pronounced sound experience. For the stretch of road you have been looking forward to all day.
Smart sound control - Always street legal
Choose your preferred mode and let the technology work in the background. Smartbox monitors the motorcycle’s engine signals and adjusts valve operation when required by the applicable sound regulations. Your selected mode remains subject to these automatic interventions, bringing adjustable sound and homologated operation together.
4-Year Warranty
Quality is something you should feel every time you ride. From the carefully selected materials and premium finish to the precise fit and dependable electronic control, every detail of a Dr. Jekill & Mr. Hyde exhaust is developed with lasting enjoyment in mind. The result is a system that looks at home on your motorcycle and delivers effortless sound adjustment, ride after ride.
That commitment continues long after installation. All our products come with a standard four-year warranty, giving you lasting confidence in the craftsmanship and technology behind your exhaust. Whether your Sprint is part of your daily routine or your reason to head out at the weekend, you can look forward to years of riding with a sound of your own.
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Dr. Jekill & Mr. Hyde systems embody three distinct personalities: the Dr. Jekill mode, the Dynamic mode and the Mr. Hyde mode. By a simple push of a button a valve inside the muffler closes, opens, or opens halfway, giving your exhaust more power and sound. This gives you all the tools to adjust your sound to the moment. Our software is programmed to intervene subtly and almost imperceptibly when the parameters set by the legislation are reached. This ensures that you are street legal in all riding modes.
Dr. Jekill & Mr. Hyde | The Exhaust is a completely legal exhaust system that complies with European laws and is ECE, EG-BE and TÜV approved. The reason for this is that every Dr. Jekill & Mr. Hyde system contains a smartbox: this electronic control unit is the brain of the product and contains software that reads CANBUS signals coming from the motorcycle’s ECU.
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The BOLT electronically adjustable exhaust brings almost 30 years of Dr. Jekill & Mr. Hyde expertise to the Harley-Davidson Sprint 440. From its textured black finish to its precise fit and electronic sound control, every detail reflects our commitment to quality.
Each system undergoes extensive testing to withstand heat, vibration, weather and everyday use. High-quality European materials from trusted suppliers provide the foundation for durable construction and dependable operation. The result is an exhaust that complements your Sprint’s design, gives it a distinctive voice and delivers lasting enjoyment, ride after ride.
Your exhaust comes with a four-year warranty when installed by an authorised Dr. Jekill & Mr. Hyde dealer, subject to the applicable warranty terms. Enjoy a distinctive sound, lasting craftsmanship and confidence in every ride.
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"I will never forget the moment when my 48 was brought home to me and I pressed the button for the first time. There was an incomparable, bassy sound, as it should be for a Harley. An absolute dream for every Harley rider. For me it is optically and technically by far the best system on the market and I would buy it again 100%. The look is perfect and the riding pleasure is absolutely unique. Thank you for this simply ingenious exhaust system."
"What a fantastic sound is now coming from my Harley Davidson Low Rider S. I can't wait for the riding season to start again so I can test the system properly and enjoy the beautiful sound and performance."
"Incredibly beautiful sound! Goosebumps guaranteed, even when you start the second/third/fourth time!"
"Very very good sound, legal and loud. Neighbours are left alone and it screams out on the street."
"The best decision I've ever made to have this mega exhaust fitted! There is simply NOTHING BETTER !!! Should be standard on every Harley - I can't get the grin off my face anymore!"
"When the sound hits you in the stomach, the ground trembles under your feet and a broad grin adorns your face, then for the first time you have pressed the button on your new Dr. Jekill & Mr Hyde exhaust system. When so many beautiful things happen to you, that's worth 5 stars plus..."
"Dr. Jekill & Mr. Hyde offers the unique powerful Harley sound I was looking for. Which is more bassy, but still civil enough for daily rides. Even the possibility of adjusting the valves with just a push of a button is very comfortable on longer tours. You get something for the price and it's worth it."
"I got to know Dr. Jekill & Mr. Hyde at a motorcycle fair. I was impressed by this exhaust system from the first moment. But after a test drive I was sold. Wonderful to drive being able to play with the sound. The fact that it is legal, but still gives a beautiful deep Harley sound was the deciding factor in choosing Dr. Jekill & Mr. Hyde and they are also beautiful under my bike, also not unimportant. My bike passed the strict RDW inspection and I can confidently cross the (German) border without worrying. "
"If you are looking for a high quality and exactly finished exhaust system which can be modified to your own style you have to choose Dr. Jekill & Mr. Hyde! On top you also get the possibility to change your sound levels easily by a push of a button."
"I am very satisfied. Great look, mega sound and still legal. It was worth it."
"It's just awesome I can ride my bike to work at 5 a.m., without getting into trouble with the neighbors! But when I'm on the open road, press the button on the handlebars and the valve in the muffler opens, the show begins! The best sound you can imagine, bassy, muffled, every meter I ride becomes an experience for my ears and soul! Without worrying about a traffic control! I can only recommend: get a system, it is worth every penny."
"I have installed my second J&H system, first on my HD Custom and since 2018 on my HD FatBob BJ 2018. What can I say, the sound is really perfect, not too loud, but also not too quiet, a bass tone, that fits the bike perfectly. I also looked and listened to other manufacturers, but then decided in favor of J&H. The advice and after sales service at J&H is great and I personally recommend all my biker friends to buy from you! The BEST! "
"Just awesome, no comparison to the original sound. I would never go without a Jekill again."
" Today was my first ride on my Road King Special with the J&H exhaust. What a revelation. It felt like a brake had come off the bike and the sound is magnificent. This is the best upgrade you can do on your bike. My bike is Euro 5 and there it still works. The sound of the Mr. Hyde mode is warm and dark. The looks are also great. This exhaust is just what you need on your bike."
"Dr. Jekill & Mr. Hyde is the best investment in my bike so far!!! It adds 100% more driving fun. I can adjust the volume according to my needs, and at the push of a button a roaring sound and pure performance. And the best of all it's street legal. Many thanks to the Dr. Jekill & Mr. Hyde Team - great job keep it up!"
"I've hesitated for a long time to buy a Dr. Jekill & Mr. Hyde exhaust system. This year I finally got the heart to configure and order the exhaust system according to my wishes. After the exhaust system was mounted on my Harley-Davidson Breakout and I picked up the machine, and I was fascinated by the sound after the first 5 km. I haven't regretted my decision since. It's also a wonderful feeling not to be out on the road with an illegal exhaust system anymore. I will continue to enjoy the sound in my ears every mile. This is another reason for me never to buy an electric motorcycle, athough I am convinced that electric motorcycles also have a certain charm. But unfortunately I am a person with emotion - the sound of the motorcycle has to be top notch."
"Very good exhaust system - perfect finish and street legal. And Smartbox 2 is awesome!"
"Just WOW! I've had a motorcycle license since I was 18, but I've never bought a bike. My dream was to buy myself a Harley by the age of 40, but it didn't quite work out. But shortly before my 41st I did. The Dr. Jekill & Mr. Hyde system simply rounds it off, it is pure riding pleasure when you are out and about in Mr. Hyde mode. That's how a Harley has to breathe. Just yesterday, I rode to a gas station, and when I came out again, my bike was being inspected by another Harley rider. I just said, can I help? His answer: just wanted to see what you're riding, it sounds mega, I got to have it. I can just say thank you! Legal with perfect sound."
"The perfect finish when it comes to design. For me, no other system was ever considered. EURO 5 and the push on the button lets us know why we ride Harley."
"I've never regretted the decision to go with the Dr. Jekill & Mr. Hyde system and I look forward to every trip with the beautiful, deep and powerful sound. There's a night mode for those who come home late at night ;-) "
"From my point of view the best sound by far. This is exactly what a Harley-Davidson should sound like, nice and bassy. The Dr. Jekill & Mr. Hyde increases the driving pleasure by 100% and if you want to be a little gentler on the road, you always have the option to choose between the 3 levels. In addition, the quality and service are unbeatable, in my opinion the BEST system on the market. I don't want to be without them on any machine and would recommend them anytime."
"When I ride with my motorcycle I feel free. And when I ride with my Dr. Jekill & Mr. Hyde exhaust I feel like I'm the king of the streets. And when everybody looks at me and give me a thumbs up I know I made the right decision choosing this exhaust system."
"So, What I particularly like about the Dr. Jekill & Mr. Hyde exhaust is the deep sound, the quality and that the valve is inside the silencer. I also think it's great that you can change the look of the exhaust afterwards by replacing the end caps. 100% legal and yet the full Harley sound is absolutely great, especially in Germany."
"Simply awesome!!! The unique sound makes every kilometre in the saddle a (sound) experience and hey, each of us only has 1 life, so I can only say to anyone who is still thinking: don't hesitate any longer and get a Dr. Jekill & Mr. Hyde exhaust immediately and you will enjoy every second on your bike even more, I promise!"
"This exhaust system is everything the manufacturer says it is. Keeps the peace in my home and neighborhood and gives the perfect sound."
"When I bought a Harley Davidson Sportster Forty-Eight, it quickly became clear to me that I had to replace the exhaust system. Of course, only one exhaust system was an option for me. The quality, optics and of course the sound of the Dr. Jekill & Mr. Hyde is simply unique on the market and all of this is still 100% legal. I would also like to highlight the great selection of end caps at this point, which allow each customer to customize. The change from the original system to the Dr. Jekill & Mr. Hyde exhaust system, transformed my Harley's sound from a lawnmower into a black beast. As soon as the infamous button is pressed, the hair on the neck stands up. Emotions and moments of happiness that Dr. Jekill & Mr. Hyde gives every motorcycle rider with their products. "
"I have my Dr. Jekill & Mr. Hyde exhaust for one year now, 6.500 km on the 2019 Street Bob 107ci stage I with S&S teardrop intake... and VERY HAPPY! Amazing sound, deep, dark and loud, but quiet when necessary (neighbours, city center, horses or small kids around...) all this legal with certificate. This head-turing piece of art is a must-have on your bike!!"
Q: Is the BOLT exhaust street legal in Europe?
The BOLT exhaust is being developed to comply with the applicable European regulations. Final approval documentation will confirm the models and configurations covered. Smartbox technology monitors engine signals and automatically adjusts valve operation when required to stay within the homologated limits. Your system’s approval documentation confirms the models and configurations covered.
Q: What makes BOLT worth the investment?
BOLT will combine three electronically adjustable sound modes with a design developed specifically for the Harley-Davidson Sprint. You’re investing in precise fit, premium construction and intelligent sound control, backed by almost 30 years of Dr. Jekill & Mr. Hyde expertise. From quiet departures to a fuller, more expressive ride, it brings a choice of sound to the journeys you make every day.
Q: What warranty do I get?
When installed by an authorised Dr. Jekill & Mr. Hyde dealer, your BOLT exhaust comes with a four-year warranty, subject to the applicable warranty terms. Your dealer can explain the coverage and help with any service or warranty questions when the exhaust is released.
Q: How do I switch between the three sound modes?
Use the handlebar-mounted button to select Dr. Jekill, Dynamic or Mr. Hyde mode. Choose a restrained exhaust note, a balanced everyday tone or a fuller sound to suit the moment. Smartbox remains active in every mode and automatically manages valve operation when required.
Q: Where can I buy and have the Bolt exhaust installed?
The BOLT is not ready to order yet. An authorised Dr. Jekill & Mr. Hyde dealer can confirm availability and compatibility for your Sprint, explain the available options and arrange professional installation. They’ll also show you how to operate the system, so you can enjoy all three sound modes from your first ride.
Q: Can I hear the Bolt exhaust before I buy it?
Once release, contact your authorised Dr. Jekill & Mr. Hyde dealer to ask about a sound demonstration for the Sprint. Hearing Dr. Jekill, Dynamic and Mr. Hyde modes in person is the best way to experience the difference and find your favourite sound.
To make sure you don't miss out on any updates about the exciting development of the BOLT exhaust for Harley-Davidson Sprint, we invite you to sign up. By doing so, you'll be the first to know about the latest news, exclusive releases, and when this remarkable exhaust becomes available. Don't miss out on this opportunity to stay in the loop and be a part of our journey!
