In the past few weeks, we have covered basic engine components and their relationship to the overall performance of the motorcycle. The topic this week is the exhaust system, and what a variety of exhaust systems there are...

Before sitting to write this I asked around to see what other riders looked for when purchasing a set of pipes. I wasn’t too surprised to hear that the sound and style of pipe was usually the selling feature. Some like them loud, others need a look to put the finishing touches to a well thought out custom. Only a few throttle jockeys said they shop for an exhaust because they want the most performance out of the exhaust.

 I’ve seen on numerous occasions people buy a set of pipes because they saw them or heard them on another bike. Since there are so many different types of exhaust systems for your bike, it is important to take note of what you are adding when switching over to a new system. The Harley engine likes just the right amount of back pressure, not too much and not too little. Exactly how much differs depending on the displacement, and where in the power band it will be running. Certain exhaust pipes are more free-flowing, while others are more restrictive. Systems with a 2-into-1 design often help scavenge the exhaust better than separate 2-into-2 pipes, although this will also differ depending on how your engine is built.

 Now a lot of people say that the H-D is the most finicky engine when it comes to pipe selection and back pressure, and I would have to agree. Large diameter pipes are great for drag bikes, which make their power up high in the revs with 100-plus cubes. Small pipes can be great for torque, but can pinch off the top end. So, buyer beware, bigger is not always better especially if you are sacrificing valuable back pressure.