On their own they do add a little. But the power gain really shines when combined with a replacement air cleaner assembly as well. That's two thirds of what people refer to as a Stage 1.

The simple explanation... The engine is essentially an air pump. If some air is good, more is better. Most aftermarket slip-ons and full exhaust system make it easier for the bike to exhale. Similarly, most air cleaner assemblies make it inhale better.

But there is fuel in there too. That's where the third part of the Stage 1 comes in. The engine operates best at a specific ratio of air and fuel. Since you have added more air you must give it more fuel to maintain that specific ratio. In a carbureted bike that is a relatively simple task; you replace the jets inside the carburetor with larger ones. In a fuel-injected bike you must reprogram the fuel delivery module, telling it to give more fuel.

That’s slightly oversimplified as there are some tuning procedures necessary to get things just right. There is also a required order of operations (can't effectively rejet until you have the intake and exhaust done, shouldn't run the air cleaner without the fuel adjustments, etc). In any case, that’s the basics of the process. So the answer to your original question is yes, adding exhaust does add some power. Slip-ons mostly fall between a $100-$300 price range.

The combination of intake, exhaust, and tuning (a.k.a. Stage 1) is the single largest, and simultaneously least expensive, performance related modification you can perform without going inside the engine. I'm sure others can eloborate further but I believe the estimated gains from a Stage 1 upgrade are somewhere between 10-17 HP depending on components used and how well it's tuned.

 

A lot of people go with V&H. I can't knock them because they do sound pretty good.

At the same time though I think the CS slip-ons sound just as good and in most cases can be had for a fraction of the price of V&H.

 

good explanation... I knew its to improve flow into and out of the engine. My question is, if slip ons are as good as replacing the exhaust itself. I thought slip ons were just for sound Ithought you needed to replace the exhaust to get power.

 

Guess I've been doing it wrong. Hacksaw, chisel, cutting torch&mig welder.