Jekill & Hyde Exhaust Systems: Making a big noise at the flick of a switch! - Motofire

Jekill & Hyde Exhaust Systems: Making a big noise at the flick of a switch!

Dr. Jekill & Mr Hyde have been making a noise from their exhaust systems for years, but as they move from ‘custom’ machines into the more mainstream, ‘street’ market, are they worth the price?

As we sit in the car heading back towards Amsterdam’s Schipol airport, Morten from Norway’s Biker Journalen magazine is surprised that before today, we’d never heard of Jekill & Hyde exhaust systems,

‘For us, they’re really popular’, he states with pride, ‘but then we are really strict, unlike you crazy Brits’.

It’s an interesting, almost counterintuitive notion; the idea of the stereotypically reserved, polite and genial British public being thought of as crazy and somehow irresponsible, but it’s one that both Ian and I have to battle with over the course of our factory tour around the premises of Dr Jekill & Mr Hyde. Because on the face of it, the tuned exhaust systems that the company produce, are essentially concerned with compliance to the law.

First, some statistics…

Ten seconds of a motorcycle engine and exhaust bellowing at your ears is the equivalent of standing in thirty minutes of heavy traffic. In order to counter this noise pollution across the region, the Euro4 regulations are now impressively strict, meaning that many custom exhausts available for motorcycles instantly make your bike illegal for the road from the moment that you fit them.

To give you some example as to how rapidly these environmental laws are changing, the Euro1 law – which came into effect in 1999 – allowed exhausts to release no more than 13.0g of Carbon Monoxide every kilometre. In 2016 and with the introduction of Euro4, that requirement is now dropped to a relatively tiny 1.14g for every kilometre travelled. And as with gases, noise pollution is being tackled just as aggressively.

Whilst we here within the UK seem to be perversely proud of sticking the proverbial finger up at the EU, there is no escaping the fact that manufacturers must comply with these new regulations, and that our motorcycles are only going to become more ‘restricted’ when it comes to what is possible from a machine leaving the factory.

All of which goes someway to explaining how these exhaust systems came into being, but what it doesn’t do is demonstrate just how much difference such a ‘tuned’ exhaust can make to a motorcycle, and just how much damn fun it is to be able to alter the note – from quiet, to booming bass, to sedate again – at just the touch of a button. Literally.

As we head out onto the roads around Venlo, a small city towards the South East of the Netherlands and nestling towards the border with Germany, Ian takes control of an Indian Chieftain whilst I swing a leg over a Harley-Davidson Breakout. As we start our engines both exhausts burble – gently – into life.

Immediately I press the unfamiliar, milled button mounted onto the left handlebar and it flashes into action, I gently rev the throttle with my right hand and within half a second the sedate burble is replaced with a throaty, bass-ridden roar. I snigger to myself gently, ‘haha, this is going to be fun’.

The primal need to generate as much noise as possible from an engine, is a strange function of the human brain that I’m not going to attempt to answer here. As much as I’d like to go into the many reasons that I believe that ‘loud pipes save lives’ is a proven myth and that electric motorcycles don’t need to make noise in order to be ‘accepted’, the fact of the matter is, that every time I press the Jekill & Hyde exhaust button – something that I do many hundreds of times during the course of our ride – a grin the size of an Edam cheese wedge forms on my face that I just can’t shake.

This button is magic.

Push it once and it rotates the valve in the exhaust from fully closed to fully open. Push it once more and it closes within an instant, taking what is essentially a roaring, open exhaust back down to a fully baffled engine note.

Jekill & Hyde say that for legal reasons their systems are only allowed to affect noise and/or performance by a margin of 5% (either up or down), but when you’re talking about Decibels (dB) that 5% can make an instant difference. Each bike that I ride with the system impresses with its ability to alter the tone and volume of the exhaust note, but what equally impresses is the obvious time and attention that has gone into tuning the output of every, bespoke implementation.

The BMW rNineT that I ride next, rides just like any other BMW rNineT (and any performance gains (or losses) must – by European law – fit within that 5% bracket) but when I open the valve from fully closed to fully open the act of pushing that button somehow makes me feel like a fighter pilot, and with the encouragement of a healthy growl coming from the exhaust, I instantly feel as if I’m riding faster.

How is it that just pushing a single button can feel so empowering?

But this isn’t simply a gimmick, as my next ride on a Harley-Davidson Forty-Eight teaches me.

You could be forgiven for thinking that a system like this is the ‘grown-up’ equivalent of putting a playing card between the spokes of your bicycle; all it’s doing is making you think that your bike sounds cool. But as I ride through a local town at 30km – valve fully open – I notice the people sat in the café by the side of the road looking less impressed and far more disgusted at the thundering rattle this parade of motorcycles is making.

I reach for the button, push it once, and the system instantly calms the rumble coming from my motorcycle.

In fact, the difference on this particular set-up is so noticeable that I find myself switching it on and off at every opportunity; there’s a horse! Sound off. There’s a nice bit of straight road! Sound on. Watch out for that cyclist? Sound off. That bloke is staring at me like I’m a menace to society! Sound back on and accelerate wildly to annoy him even more! (We’re not always angels).

It’s basically a noise cancelling/raising button at this point. And it’s brilliant.


The system is electronic, and the idea behind the rotating valve within the exhaust-can is itself simple. But if there is one thing that the tour today has taught us, it’s that perfecting the simple things can be hard.

Having worked on their offering since the first version way back in the 1990s, Jekill & Hyde are proud to make that claim that not one of their systems has ever been returned for a stuck valve, or for a problem within the mechanism itself. I do a quick calculation in my head, raise an eyebrow – and a hand – and look Shorty, employee number three of a now seventy-plus sized company, square in the eyes. He stares directly back at me, ‘No. Not one has ever been faulty’. I look back down at my notepad suitably admonished.

There’s no doubting the clever engineering and the quality of the components used within the J&H system. It’s something that hits you from the moment that you see the cost of a standard set-up; but at €1,500 and upwards, it’s fair to say that this system isn’t aimed at everyone. In fact, a quick browse of their website configurator shows that a basic system for a brand new Forty-Eight is €1681 excluding VAT. That’s a fifth of the cost of a brand new Forty-Eight itself.

So who is a Jekill & Hyde exhaust system for?

Well, first off in countries where the laws are severely strict about noise emissions – and the new Euro4 limits are extremely strict – the system is fully legal. And fully legal at all times. This means that anyone concerned about the noise that their bike is making can ride comfortably knowing that they’re not going to be pulled over by the ever helpful boys in blue.

Or at the very least, if you are asked to stop by the side of the road whilst they examine your motorcycle, you can be safe in the knowledge that your exhaust can isn’t going to be the thing that they arrest you for.

Secondly, the looks, styling and quality of these systems easily dictates that if you’re the kind of person who likes to customise your bike, then you should at least take a cursory look at what Dr. Jekill & Mr. Hyde have to offer.


And finally, there are those amongst us who spend money on things that make us happy.

And if you have the money to spend, like the idea of riding a street legal machine that makes a little bit more noise when you want it to, looks good and makes you feel like the King of your domain at the push of the button, then this just might be what you’re looking for.

Full Disclosure:
Jekill & Hyde wanted us to test their system so much that they flew us to Amsterdam, made us ride in a taxi for two hours and then fed us dinner. They also wanted to get rid of us quickly, so they flew us home the next day.

Steve Hunt

Steve Hunt

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Steve fell in love with motorcycles at an old age. Call it a mid-life crisis, call it fate, but nothing can keep him away from feeding his two-wheel addiction.


3 Comments Join the Conversation →

  • A Rider

    The price is an order of magnitude too expensive for all but a small fraction of riders ( Jay Leno would probably buy one without a second thought ). I’d pay $200 for such a setup, but a price higher than that and I’d either fabricate my own system ( it’s not rocket science ) or do without.

  • Clutchman11

    No it’s not. Now try getting that homemade setup to comply with all regulations stipulated by Euro 4, as that is what I’m getting out of the story. At a guess there’s more to the story than just being able to open and close a valve in an end-can.

  • Pete

    I think the reason why high end manufacturers don’t have this button system as standard is because they already have valves that open automatically at certain revs… the extra money in having the button rather than automation isn’t really worth it IMO.