Exhausts systems for motorcycles can be very beneficial to the owner. Motorcycle exhaust systems can include the header, collector pipes and the muffler canister. Motorcycle exhaust systems can improve the sound, improve hp and torque, are lighter and many look much better than stock pipes. First is the header which has the duty of directly tuning the engine exhaust pulses. The diameter and length of the header pipes is very critical to keep the speed and volume of the exhaust correct. The headers continue until they reach the collector where multiple pipes will connect into the main tube running into the muffler. The diameter and volume are also critical for best power results. Many different styles of motorcycle exhausts exist for different types of bikes. Inline four cylinder bikes will generally use 4 into 1 (meaning four headers running into one collector pipe) and one muffler.
To increase the midrange torque on inline four cylinder engines, sometimes the 4 into 2 into 1 header pipes are used. For v twin motorcycles three types of exhausts are used. For harleys most people like twin pipes, that usually have a crossover (connecting pipe) to increase the mid range torque. This crossover pipe usually does not affect the peak horsepower much. Harley owners generally love twin pipes with straight through mufflers for that harley sound. Sport motorcycles will also generally use a twin muffler arrangement for best top end horsepower. Many v twin owners including Honda and Suzuki bikes are modifying their own exhausts by using an extension for a drill and a hole saw to bore a hole through their muffler canister baffle. This will produce the v twin sound cheaply, with little change to the tuning. Ducati and many other twins are also using two into one into two muffler exhausts. This arrangement uses a short collector between twin pipes and is a good compromise of power everywhere. Some v twin bikes also use a two into one exhaust and only use one muffler. This system will almost always increase your mid range torque alot and lose a little hp. It could also make more power on some bikes, like harleys, due to the firing order arrangement of the engine. Many harley owners purchase the full exhaust system. These systems are usually steel and chromed to match the bike. Sportbikes generally only purchase the collector pipe and muffler or just a slip on muffler. Most of the time the headers are very good and are left alone. The slip on mufflers are very light compared to the stock canister. Slip on canisters are made from stainless, aluminum, titanium, and carbon fiber. The last three being very light also. Slip ons are also usually straight through mufflers like harley pipes. Noise doesn’t have to be an issue on any bike depending on the manufacturer of the exhaust system. Most motorcycle riders agree that some exhaust noise can actually be safer, due to people hearing that you’re there. Horsepower gains can be anywhere from almost nothing on an already excellent system. Most systems will gain around 5 horsepower. Some systems could gain over 10 horsepower depending on the motorcycle. With many options today it’s no wonder most motorcycles on the road today have aftermarket exhausts.