The ROAR of the machine sometimes can replace the horn in the middle of the traffic, sometimes is similar to the ones that snore so loud that look like the lion king sleeping in the middle of the forest, but there are also the quiet guys that go like a ninja and no one can listen to them. It all depends on how you want to go and make yourself noticed.
In a simple way, an exhaust system has the function to capture combustion gases that occur in the engine block and throw this gases away to the outside world. The main gas produced with the burning of the fuel is the carbon monoxide and is converted to carbon dioxide by the catalytic converter which is less dangerous to us before being sent to the atmosphere.
Starting from the top, an exhaust system has its head, this is the piece that connects the engine block to the pipes is where the air is going to flow from and to the open air. If we want our gases to be expelled more quickly we should adopt only one single exhaust way of flow, but there is the heat problem if the tune is not well made in the admission of fuel to the engine. In two cylinders engines, we can usually see the 2-1 system that converges the air from the engine to the pipes. In four cylinders engines, the most usual configuration is the 4-2 but we can improve that to the 4-2-1 or even to the 4-1, once again it will need some tune to prevent the flames from going out from your mufflers or even the heat issue that was mention before.
Also, we have to remember that the cylinders don’t run at same time, so the release of the gases must be synchronized so that the gases do not create a back pressure and a restriction on the engine performance. This issue takes us to the pipes, where some curves will do that perfect sync so that the engine run and breathes perfectly.
In the end, we have the mufflers. Here is where the catalytic converter is placed. The mufflers are the part we look first in the whole exhaust system. They are the key factor to the loudness of your bike. Some of them have glass fiber to make the sound less aggressive, but it will burn with time, some of them don’t have anything at all, but your bike will sound like a beast roaring in the middle of the jungle.
Just don’t be the one that awakes everybody at night when you arrive safely home.