Slip on motorcycle exhaust systems; just how good are they?

Slip on Exhausts: A Beginners guide...

Choosing a slip on motorcycle exhaust can be a daunting, some might say impossible prospect due to the sheer number of slip on cans available. But why do so many motorcyclists want to go through the hassle of finding suitable slip on motorcycle exhausts in the first place? After all the original is deemed to be suitable for the bike in question, right? And you can bet your bottom dollar that the can fitted to the bike will meet all the necessary noise and emissions requirements, no matter where the bike is being sold. So why put yourself through all the pain?

Well without putting too fine a point on it, we are power mad! We are obsessed with squeezing every little horsepower out from our bikes, and the slip on motorcycle exhaust is one surefire way for anyone with even the bare minimum of mechanical know-how to achieve a small power gain and also boost the sound and the look (lets not forget the look) of the bike.

To get a full power increase right through the power range of the bike (any bike) you would have to go through a full system installation, then follow that up with some careful re jetting of the carburetor or re- mapping the fuel injections control unit. However the addition of an aftermarket slip on motorcycle exhaust will almost definitely add a few bhp at peak power, while smoothing out those power dips in the lower to mid range of the bikes performance.

Now, as regulations get stricter and stricter, they are starting to affect the designs of a number of slip on exhaust manufacturers. Many of them now offer slip on cans with removeable baffles. Leave the baffles in and you've got a street legal, quiet good looking slip on with a modest power gain. Take them out, and you've got a reasonable copy of Valentino Rossis exhaust! (well maybe not quite that good, but you get the general idea...).

But how good are these slip ons? How easy is it to install a slip on motorcycle exhaust? What is the noise gain, and more importantly, what is the improvement in performance with an aftermarket slip on exhaust?

Well let me enlighten you. In a recent test conducted by a UK motorcyclist magazine, several top exhaust manufacturers submitted their slip on exhausts for a test to determine just that. Some of the top makes were included, like Akrapovic , Yoshimura , Micron, Laser, Devil, to name just a few. All the exhausts were tested on different bike models; the Honda Fireblade, Suzuki GSX 600 and the Honda CB 1300 .

The results were nothing short of amazing. Every slip on exhaust tested on every bike was able to show between 1 and 8bhp power gain at full output, depending on the bike (the bigggest gains were seen on the CB1300) Don't forget, the gain will depend on the bike and the quality of the OEM exhaust originally fitted, but its nice to know that these exhausts do what the makers claim! As you would expect, along with the power gain comes an increase in noise from the slip ons.

The other interesting point was that the slip on exhausts with removeable baffles that were included in this test actually showed a power decrease with the baffles in. It was only with the baffles removed that the cans showed an increase in power (quite considerable in some cases)

What about fitting? well the time taken to remove the OEM can and fit the new slip on exhaust was on average 20 minutes. Not bad! Well actually there is one minor problem when fitting a new slip on exhaust, but only if your bike has an underseat exhaust like the Fireblade: the time taken for fitting in this situation stretches to close to an hour and a half!

Which slip on exhausts came out best? Well this is only my interpretation of someone elses results but Akrapovic and Yoshimura scored very well on all the bikes. Mind you the other models tested weren't very far behind, and with those two names you get perfromance but you are definitely going to pay for the privilege!

There are some great places online to buy slip on exhausts. Here are my top three outlets....

Oh and if slip on motorcycle exhausts for street bikes aren't your thing, try for an easy cruiser add on from a range of suppliers including Vance and hines, Cobra, Jardine and many more!

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Copyright Motorcycle parts accessories and more, Michael Holmes 2004