Dr. Jekill & Mr. Hyde® 4.5" Electronically Adjustable Exhaust for Harley-Davidson CVO 121 Models (2023+)
This complete bolt-on kit includes everything needed for installation.
Includes:
- 4.5" Dual Slip-On Exhaust System in Chrome or Dark Chrome
- Electronically Adjustable Control Kit
- Mounting Hardware
The Dr. Jekill & Mr. Hyde® 4.5" Exhaust for Harley-Davidson CVO 121 models (2023+) is a street-legal, electronically adjustable exhaust system designed to deliver the ideal blend of sound, performance, and comfort while preserving the premium look of your bike.
One of the standout features of this system is its factory-style CVO appearance. The finish is designed to match the original stock look, and the included adapter allows you to retain your original Harley-Davidson CVO end cap—giving you the signature CVO style with Dr. Jekill & Mr. Hyde® technology.
With the signature electronically adjustable system, you can control your exhaust sound at the push of a button:
- Dr. Jekill Mode – quiet and refined
- Dynamic Mode – deeper, more balanced tone
- Mr. Hyde Mode – full, deep rumble
Engineered to complement Harley-Davidson’s VVT engine, this 4.5" dual slip-on system delivers a deep, harmonized exhaust note while maintaining OEM fitment with stock components.
Fits Harley-Davidson CVO 121 models (2023+):
- CVO Street Glide
- CVO Road Glide
Features:
- 4.5" dual slip-on design
- Electronically adjustable exhaust system
- 3 selectable sound modes
- Available in Chrome or Dark Chrome
- Compatible with OEM CVO end caps using included adapter
- Bolt-on installation
- OEM fit with stock cases and passenger footpegs
- Street legal
- Stainless steel construction
- Active Smartbox technology
- 4-year warranty
Customize your exhaust your way using our online exhaust configurator.
The Ultimate CVO 121 Exhaust
Sound Check
HD CVO 121 // Soundcheck
USE YOUR HEADPHONES FOR THE ULTIMATE EXPERIENCE
LISTEN AND ENJOY THE THREE DIFFERENT SOUND MODES OF THE DR. JEKILL & MR. HYDE® - THE EXHAUST.
Mr Hyde
The exhaust boosts a beautiful, deep rumble.
Dynamic Mode
A tamed Mr. Hyde sound.
Dr Jekill
A calm, low-key but distinctive sound.
Technology
The Valve
At the heart of every Dr. Jekill & Mr. Hyde® exhaust system is the valve, the technology that makes The Exhaust truly unique. Electronically adjustable on the fly, it gives you full control over how your bike sounds, with three distinct modes that adapt to the moment. From a refined, more subtle tone with the valve closed, to a deeper, more aggressive character in Dynamic Mode, all the way to the full, uncompromising sound of Mr. Hyde with the valve wide open, you decide exactly how your bike performs and sounds every time you ride.
Innovation
Research & Development
At Dr. Jekill & Mr. Hyde®, innovation never stands still. Every exhaust system is born from intensive research, advanced engineering, and relentless testing under real-world and extreme conditions. Inside our state-of-the-art facility, we are constantly pushing our products harder, refining every detail, and improving every system to stay far ahead of the competition.
From sound control and valve technology to performance, durability, and long-term reliability, nothing is left to chance. Every part is tested, every system is challenged, and every improvement is driven by one goal: to build the most advanced exhaust system on the market.
Craftsmanship
Premium Quality
For over 30 years, Dr. Jekill & Mr. Hyde® has defined the standard in premium exhaust systems. German engineered and Dutch handcrafted, every system is built in Europe to deliver unmatched sound, aesthetics, and performance. Designed to withstand extreme heat, harsh conditions, and years of riding, each exhaust is rigorously tested and built using premium stainless steel and advanced Nomex packing for lasting durability. This is not your average exhaust system, this is craftsmanship without compromise.
Frequently Asked Questions
Do You Have Questions?
Here we answer the most common questions about Dr. Jekill & Mr. Hyde® exhaust systems.
Dr. Jekill & Mr. Hyde® systems are premium exhaust systems built around engineering, materials, fit, finish, and electronically adjustable sound control.
Each system is developed specifically for the motorcycle, designed as a precise fit, and built with advanced components like the electronically controlled valve system that gives you multiple sound modes at the push of a button.
You are not just buying a muffler. You are buying a complete premium system with advanced technology, model-specific development, and a 4 year warranty.
If your bike is completely stock, no tune is required.
Our exhaust systems are German engineered to perform properly in every sound mode and are developed around a stock motorcycle setup.
If your bike has aftermarket modifications such as a decatted header, cam, or high-flow air filter, we recommend contacting your local dealer or reaching out to us directly so we can advise you on the best setup.
No, not if you are installing our exhaust on a stock bike.
Our systems are designed as plug-and-play solutions for stock motorcycles and do not require a tune.
To take it a step further, in Europe we are an official partner of Harley-Davidson, and our exhaust systems are available exclusively through authorized Harley-Davidson dealers.
While the setup is a bit different here in the United States, that partnership reflects the strength of our relationship with Harley-Davidson and the level of trust our systems have earned at the corporate level.
No. Dr. Jekill & Mr. Hyde® exhaust systems are designed to be plug and play, with a precise fit for your motorcycle and no complicated modifications required on stock applications.
Installation is straightforward for any mechanically inclined person. If you are not mechanically inclined, please have the system installed by your dealer.
You can buy our exhaust systems directly through us, through our dealers, or at events.
If you want help choosing the right system or locating a dealer, our team can point you in the right direction.
