topbanner ad

Tuesday 24 November 2020

Dr. Jekill & Mr. Hyde

'Project 21' - Electronically Adjustable 2:1 'Clubstyle' M-8 Exhaust

Famous for its EU approved electronically adjustable exhaust systems, Dr. Jekill & Mr. Hyde (J&H) has a new Clubstyle 2:1 that is the result of "months of design, prototyping and testing," according to J&H's Sjoerd Ottenheim, the Product Manager for the project. "Finally we are ready to present the 'Twenty-One' - a unique and electronically adjustable 2:1 exhaust for Milwaukee-Eight Softail models."

Staged at the Venray Circuit in the Netherlands (formerly known as Circuit de Peel), the launch took place with the unveiling of a new project bike and group of Clubstyle motorcycles that showcased the sound of the exhaust - "a full, deep sound," says Sjoerd.
“The Twenty-One produces a sound that really takes the power of the M-8 engine to new heights - it really is a surprise, and the better feedback from the exhaust really enhances the riding experience. It challenges the rider to demand that little extra from the M-8, and the 'Twenty-One' delivers.
"The exhaust has been subjected to extensive sound tests to create this exceptional sound experience. It has been designed with input from a specific group of performance and Clubstyle riders. 

"First as a design in the computer, then as a 3D model, after which we could proceed to make a prototype. There was more to making this exhaust than just the sound of course. While sound management is what we here at J&H are best known for, the materials, the finish, the emissions and the power, in terms of hp and torque, all influenced the development and the final result. 

“The headers and muffler are made of stainless steel to achieve the balance between performance and legal requirements. There are different color end cap options available, all specially developed for the M-8, but we also expect to be able to evolve this first M-8-specific 'Twenty-One' for additional models in the future - additional Harleys and other brands too."
The 'Secret Sauce' that J&H brings to exhaust sound management is its unique electronically controlled and handlebar-operated valve system.

"Our exhaust systems embody three different personalities: the Dr. Jekill mode, Dynamic mode and Mr. Hyde mode. With a simple push of a button, the valve that is placed halfway up the muffler closes or opens, which provides more sound and performance. According to the riding circumstances you can choose whether you are in the Dr. Jekill mode (mild), Dynamic mode (responsive) or Mr. Hyde mode (not so mild!). The rider decides.
"Either way, the Dr. Jekill & Mr. Hyde exhaust is a completely street legal system and complies with European legislation and laws - in short, while your riding style might be able to get you into trouble, with J&H the exhaust can't!"
The production edition 'Twenty-One' will be available in heat resistant brushed or matte black finish and offered for M-8 Softails.


Tech Spec for 'Clubstyle'
H-D Softail Low Rider S
by Mario Kyprianides, Chopper Kulture

  • Engine: 114" H-D M-8
  • Air intake: Ness (CCE)
  • Cam chest kit and vented dip stick: Feuling
  • Gaskets: Cometic
  • Clutch cover, forks, sprocket: Cera Carbon
  • Clutch cable: Barnett (CCE)
  • Tuning: Don Performance
  • Exhaust: Dr. Jekill & Mr. Hyde
  • 'Project 21' two-into-one
  • Frame and wheels: Harley-Davidson
  • Skidplate: Speedmerchant
  • Adjustable suspension: Hyperpro
  • Brakes: Rebuffini and Brembo
  • Brake lines: Goodridge (CCE)
  • Saddle: Saddlemen
  • Indicators: Kellermann, Atto Black
  • Hand controls, grips and mirrors: Rebuffini
  • Fairing: Memphis Shades
  • Handlebars, levers and Flo footrests: Factory Frankfurt
  • Handlebar bushings: CCE
  • Carbon side covers: Italian Performance Parts
  • Powder coating: MBT
  • Paint: Chikos Pinstriping, Chicano paint job

Text: Robin Bradley
Photography: Onno "Berserk" Wieringa (