The T120 Exhaust System
Electronically adjustable exhaust for the Triumph Bonneville T120
The T120 Exhaust System
$2,296.00
The Classic, Completed
Electronically Adjustable Exhaust Systems For Triumph Bonneville T120
The T120 is the Bonneville everyone pictures when they hear the name. Twin pipes, deep chrome, and a twelve hundred that has more torque than the classic silhouette lets on. 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 twin finds real body. Mr. Hyde mode opens it fully and the T120 speaks with everything it has. You choose per situation, at the press of a button.
A bike built this carefully deserves an exhaust held to the same standard. Developed for the Bonneville T120 specifically, built around its own lines and mounting points, the result of German engineering and Dutch craftsmanship. The look belongs on the bike, and the sound is new without ever feeling out of place.
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 T120 // T120 Chrome Edition // T120 Black // T120 Gold Line
The Valve
The Three Sound Modes
In Dr. Jekill mode the valve stays shut and the T120 keeps its manners. A cold start at first light, a village high street, a late run home. The bike still looks like the best thing on the road without needing to prove it.
The Exhaust
Built For The T120
The T120 is the one that defines the whole Bonneville line. Twin pipes running down both sides, chrome where chrome belongs, and a motor with far more low end than the period looks suggest. Every detail on this bike was considered, which sets a high bar for anything you bolt to it.
The electronic valve is what earns its place. Dr. Jekill mode closes it down and keeps things civil. Dynamic mode opens it halfway and the twin fills out with real warmth. Mr. Hyde mode opens it fully and the Bonneville drops the restraint entirely. 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 T120 // T120 Chrome Edition // T120 Black // T120 Gold Line
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. Both pipes warm up into a rounder, fuller note with real character behind it.
- Mr. Hyde Valve wide open. Rich and properly loud, the classic Bonneville with the restraint taken off.
In Stock Now
Build It Your Way
What you see here is what we hold on the shelf, ready to ship today. It is one of several ways this system can be built.
The full range of options is available to order. Choose your model, your finish, and your end cap, then see the whole system come together before you buy.
Configure Your ExhaustWhy 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 T120 a rich, 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
Leave Early, Wake Nobody
The best rides start before the rest of the street is up. Keep the valve closed and it stays that way.
2
Cover Real Distance
The T120 is built for long days. A sound you can hold for three hundred miles beats one you cannot.
3
Fit In Anywhere
A car park at a country pub, a slow lap of town, a full car ferry. Not every setting wants the same volume.
4
Then Wake It Up
Empty road ahead, one press of the button, and the classic Bonneville stops behaving itself.
Triumph Bonneville T120 FAQ
Still Have Questions?
The answers riders ask most often about Dr. Jekill & Mr. Hyde adjustable exhaust systems for the Triumph Bonneville T120.
This system is built for the Triumph Bonneville T120, and that includes the T120 Chrome Edition, the T120 Black, and the T120 Gold Line. It is developed for those motorcycles 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 T120 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.
