Fitting an exhaust

Stock silencers are getting bigger and fatter, while the sound just gets thinner. Rear silencers and complete exhausts from aftermarket suppliers are lighter, sound better and give an eye-catching custom look.

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Fitting a new exhaust to your motorcycle

Stock silencers on today’s motorcycles seem to be getting bigger and heavier, yet the sound they produce is more likely to reduce a passionate biker to tears than to raise the hairs on the back of their neck. Fortunately, the aftermarket suppliers offer rear silencers and complete exhausts that deliver the sorely missed throaty roar plus an authentic and eye-catching sport or custom look. But it's not just about looks. These aftermarket systems – including the street-legal versions – often deliver a performance boost and a noticeably more linear torque curve. Also, they are generally much lighter, which helps to improve the bike’s ride dynamics. Changing your exhaust is really quite simple in most cases.

A popular tuning measure for motorcycles

Owners of the current generation of naked and sport bikes (with electronic fuel injection) now have options for jazzing up the look of their bikes that would never have been street-legal in the past. Take the Hurric Supersport Exhaust, for example, with its ultra-short, cool look – what more could a biker ask for? And as if that wasn't enough, it comes complete with EC type approval! So no tedious trip to the test centre to have it approved, nor the hassle of carrying proof of road legality around with you – because the marking on the exhaust says it all!

Just replacing the exhaust, or using a K&N permanent air filter, usually still falls within the control range of the electronic fuel injection system, which ensures the correct air-fuel ratio. It's generally only when you combine two or more tuning measures (such as sport air filter plus removed dB absorber) that you need to start thinking about enriching the mixture for a fuel-injected engine (e.g. in the form of a Power Commander). This also applies if you fit an exhaust system that is not street-legal. If your motorbike has carburettors, it will largely depend on the model of bike as to when you need to adjust your air-fuel ratio – if you're only fitting an EC type-approved silencer with dB absorber, you will seldom need to add bigger jets.

Please note: But it will be essential, in most cases, if you combine more than one tuning measure (exhaust plus air filter with increased flow). After any customisation, we therefore recommend checking the appearance of the spark plugs and looking for any other indications that the engine is running lean, such as backfiring when you throttle back, or increased engine temperature. 

And what about catalytic converters? Since 2006, motorcycles have been required to pass an emissions test. If you change the exhaust of any bike built from 05/2006 onwards, the aftermarket exhaust must also be fitted with a catalytic converter in order to comply with exhaust emission standards. If you're lucky, the original cat may be housed in the manifold – in which case your aftermarket exhaust does not need to have one. Motorcycles that reached the showrooms from 2016 onwards are subject to the even stricter Euro 4 standard for exhaust and noise emissions. You must use a certified Euro 4 exhaust system. On these exhausts, the dB absorber cannot be removed. Motorbikes prior to 05/2006 do not need a cat to meet the applicable exhaust emission standards, and this still applies if you fit an aftermarket exhaust (take a look at DIY tip Vehicle safety inspection and EU law).

Fitting an aftermarket silencer: here a Hurric Supersport with cat on a Kawasaki Z750, built 2007 or later.

Before starting work, jack up the motorbike and secure it against toppling over (see the DIY tip Motorcycle Stand Basics). Lay something soft, like a blanket, on the floor so that you have somewhere safe to put both the original parts and new add-ons without them getting scratched.  


Fitting an aftermarket silencer – now let's get started

Step 1 – Undo screws on manifold, rear silencer bracket and frame

Step 1: Undo screws on manifold, rear silencer bracket and frame 

01 – Undo screws on manifold, rear silencer bracket and frame

First undo the screws of the manifold clamp, the midpipe bracket and the rear silencer bracket on the motorcycle frame. Make sure you're holding the silencer securely when you undo the last screw of the bracket so that the silencer doesn't fall to the ground. 


Step 2 – Remove cap from control shaft actuator

Step 2: Remove cap from control shaft actuator  

02 – Remove cap from control shaft actuator

Before detaching the cables from the control shaft, first undo the hex nuts holding the cables. Then you can detach the actuator cables, and use cable ties to secure them out of the way on the motorcycle. 


Step 3 – Detach cables

Step 3: Detach cables 

03 – Detach cables

Before detaching the cables from the control shaft, first undo the hex nuts holding the cables. Then you can detach the actuator cables, and use cable ties to secure them out of the way on the motorcycle.

Important: the "decommissioned" cables must not come into contact with any moving parts, so it's best to tie them up well out of the way of the chain, sprockets, rear wheel and swing arm! You can also remove the cables completely if you prefer, although this can lead to an error message on the instrument panel, which in turn could result in the bike only running in safe mode – or at least the error message will be permanently displayed. It would then have to be disabled via the electronics, which is a job that can only be done by a motorcycle workshop.


Step 4 – Insert midpipe and pre-mount manifold clamp

Step 4: Insert midpipe and pre-mount manifold clamp 

04 – Insert midpipe and pre-mount manifold clamp

Coat the contact surfaces of the pipes lightly with copper paste to make them easier to install and take apart again, if necessary. You should also use copper paste on all the fastening and clamp screws on the exhaust to prevent them rusting and seizing up. Then insert the Hurric midpipe into the original manifold and loosely pre-mount the manifold clamp. 


Step 5 – Push on new rear silencer

Step 5: Push on new rear silencer 

05 – Push on new rear silencer

Push the Hurric silencer onto the Hurric midpipe all the way. Align the silencer and midpipe so that the exhaust system is parallel to the motorcycle. Push the carbon clamp over the Hurric silencer and attach it loosely to the original mounting point on the frame of the motorcycle using the original fastenings.


Step 6 – Attach springs

Step 6: Attach springs 

06 – Attach springs

Insert the springs into the eyes provided for this purpose. This is generally easier if you use a proper spring puller tool.


Step 7 – Align silencer

Step 7: Align silencer 

07 – Align silencer

Align the silencer with the bike and ensure tension-free installation – this is important to avoid the risk of vibration damage. If the exhaust will not rest against the mounting point on the frame in spite of your alignment attempts, it's best to insert a thick spacing washer rather than simply tightening the entire system against the frame using the bolt. Finally, tighten the M8 screws on the frame bracket and on the midpipe clamp with a torque of 21 Nm. Once you've finished installing your new exhaust, and all parts are properly secured, you can carry out your first sound check. And we promise you, that sound will put a smile on the face of any biker!


The Louis Technical Centre

If you have a technical question about your motorbike, please contact our Technical Centre, where they have endless experience, reference books and contacts.

Please note!

These tips for DIY mechanics contain general recommendations that may not apply to all vehicles or all individual components. As local conditions may vary considerably, we are unable to guarantee the correctness of information in these tips for DIY mechanics.

Thank you for your understanding.