Classic Looks, Real Engineering
Electronically Adjustable Exhaust Systems For Triumph Bonneville Speedmaster
The Speedmaster is the comfortable one. Same twelve hundred, but with a pillion seat, a wider stance, and ergonomics built for actually going somewhere. Dr. Jekill & Mr. Hyde builds an electronically adjustable exhaust for it with three selectable sound modes controlled from the handlebar, available in street-legal configurations where applicable.
One exhaust, three personalities. In Dr. Jekill mode the valve stays closed for a restrained note, right for early starts and quiet streets. Dynamic mode opens it halfway and the low end fills in. Mr. Hyde mode opens it fully and the Speedmaster gets the deep, rolling voice a cruiser this size has earned. You choose per situation, at the press of a button.
The classic looks hide a properly engineered motorcycle, and the exhaust is held to the same standard. Developed for the Bonneville Speedmaster specifically, built around its own lines and mounting points, the result of German engineering and Dutch craftsmanship. It should look like Triumph could have fitted it themselves.
Dr. Jekill & Mr. Hyde electronic valve technology lets you adjust the sound on the fly. One premium exhaust system, three distinct personalities, full control from the handlebar. Backed by a 4 year warranty.
Available For
Bonneville Speedmaster
The Valve
The Three Sound Modes
In Dr. Jekill mode the valve stays shut and the Speedmaster keeps to itself. Early departures, quiet neighborhoods, a late arrival home. All handled without making an entrance you did not intend.
The Exhaust
Built For The Speedmaster
The Speedmaster gets read as the easy option next to the Bobber, and that undersells it. Swept bars, a real seat, a passenger who is actually welcome, and a chassis that handles far better than the chrome suggests. It is the one you ride all day rather than around the block.
The electronic valve suits that range. Dr. Jekill mode closes it down and keeps things civil. Dynamic mode opens it halfway for an easy rolling beat that never wears on you. Mr. Hyde mode opens it fully and the twelve hundred drops the polish. All three from a button on the handlebar, changed on the move, without stopping.
Premium materials throughout, a finish built to take weather and heat year after year, and a 4 year unlimited mileage warranty behind it. Available in street-legal configurations where applicable, and on supported stock setups no fuel tuner or ECU flash is required.
Available For
Bonneville Speedmaster
Sound Check
Hear All Three Sound Modes
Headphones or a good speaker recommended.
- Dr. Jekill Valve closed. Calm and low key, quiet enough for an early start or a slow roll through town.
- Dynamic Valve half open. The bottom end fills in and you get real weight behind the throttle, without shouting about it.
- Mr. Hyde Valve wide open. Deep, heavy, and unmistakable off idle, the sound the Bobber's stance has always promised.
Why Sound Control Matters
All The Sound You Want, Only When You Want It
A loud exhaust is great right up until it is not. Dr. Jekill & Mr. Hyde gives the Speedmaster a deep, full voice when you want one and a quiet one when you do not, and lets you move between them from the handlebar without stopping.
1
Keep The Early Start Quiet
Six in the morning on a residential street is the wrong time to make a statement. Close the valve and go.
2
Bring A Passenger
Whoever is on the back sits closest to it. Dial the sound down and a long day two up stays a good one.
3
Suit The Setting
A hotel lot at night, a main street at lunchtime, a quiet stretch of country road. Each one asks for something different.
4
Open It Up
Then the road clears, you press the button, and the twelve hundred stops being polite about it.
Triumph Bonneville Speedmaster FAQ
Still Have Questions?
The answers riders ask most often about Dr. Jekill & Mr. Hyde adjustable exhaust systems for the Triumph Bonneville Speedmaster.
This system is built for the Triumph Bonneville Speedmaster. It is developed for that motorcycle specifically rather than adapted from another model in the range.
Confirm your exact year and model in the configurator before ordering. Not certain which system you need? Send us a message and we will confirm it with you.
On supported stock configurations, no tune, fuel tuner, or ECU flash is required. The system is developed around the factory setup of the motorcycle.
Already running other performance parts, like an intake or a fueling mod? Check with your mechanic or shop first, or reach out to us and we will help steer you the right way.
Absolutely. The valve position can be changed at any moment, and you can ride in whichever sound mode you like.
Move between Dr. Jekill, Dynamic, and Mr. Hyde straight from the handlebar control, keeping things quiet when you need to and opening up the note whenever you want to.
Our Speedmaster systems are electronically adjustable exhausts available in street-legal configurations where applicable and engineered to work with the motorcycle's stock setup.
Local rules on street legality vary by where you live and ride, so it is worth checking the requirements in your area. Not sure? Get in touch before you order and we will help point you the right way.
Every system is fully plug and play. No cutting wires, no splicing. Printed instructions ship in every box, and our install videos are online whenever you want to watch ahead.
For a capable mechanic it is a straightforward job. The exact time depends on your tools, your experience, and the condition of the bike.
Dr. Jekill & Mr. Hyde® systems are premium exhausts, built on serious engineering, quality materials, exact fitment, clean finishes, and electronically adjustable sound control.
Every system is developed for one specific motorcycle and built with advanced parts, including an electronically controlled valve that delivers multiple sound modes at the press of a button.
That control is the thing a permanently loud pipe can never give you. Slip quietly through neighborhoods and noise sensitive areas, sidestep a costly citation, and stay on good terms with the people you live next to. Then the road opens up, you press the button, and the tone comes with it.
This is more than a muffler. You are buying premium engineering, advanced technology, model specific development, real everyday flexibility, and a 4 year warranty.
