By changing your air filter and exhaust system your playing with very important parts that will dramatically change your general mecanical setting. Ex: By just changing your air filter, let's say a K&N filter for instance, the volume of air that comes in your carbs will be increased, and if you dont change your carbs configuration well you will end up running on a air/fuel mixture that's going to be to lean for the original factory configuration of your bike! So the bike is gonna behave really bad, and we dont want that to happen dont we! Same thing occures when you change your pipe cannister or complete exhaust system! The result, poor performance.
There's a way of correcting the performances results mentioned above, It's very simple, you just have to have your carbs jetted with a jetting kit.One Brand that is very popular is Dynojet. By installing it you will be able to adjust your carbs settings in order to get the maximum performance of the parts that you installed on your beast!
Most dealers and motorcycle mecanics can install a jetting kit. But, the best tool that most of them dont have is a Dynomax.With the Dynomax they are able to adjust your jetting kit and carb configuration at their peek performance, thing that someone cant really acheve with only a screw driver and a couple of road test, and you will get the real horse-power and torque that your puppy dilivers!.
Pipes are made mostly for Race applications and doesnt really improve road use, Let me explain: By installing a pipe on your bike you will get more horsepower for sure, but the extra HP will be mostly situated in the higher rev (9500rpm to 1100rpm), and one thing that happens also is a loss of power in the mid range revs. So you gain and you loose! When your riding in the city for instence,well the performance of your bike will be diminish, after all you dont get to shift many gears at 9500rpm from a traffic light to an other!But the overall gain (sound and top rev HP)is really good for popping power-willies, highway dragging and waking up the neibghours!!hehe! But none of us do that, dont we!Yeah RIGHT!hehe!!
I think that the best thing to do when your thinking of changing your exhaust is to do everything at the same time, The exhaust system, The air filtersand and the jetting kit. It will save you money and time.That way you will be able to configurate your bike setting and end up with the maximum performance from each part and the bike itself.