Clean Pipe More Power

Clean Pipe =
More Power?
Have you ever heard of the theory that a clean exhaust pipe makes more power? Don’t laugh, we’re serious. And we’re not talking about the outside of the pipe, either. We’re talking about the INSIDE of a 2-stroke exhaust system.
Some race teams have found that the sound of the pipe indicates whether you’re going to make full power, or not. When they clearly hear that “ting-ting-ting” of a new pipe, the sound waves are traveling and reflecting unobstructed inside of the pipe. After a while, the inside of the pipe gets coated (injection oil, carbon) and the clean sound of the pipe is lost, and so is the best power.
What you’re most likely hearing is “shell noise”, a resonant frequency of the exterior shell of the exhaust system. When the inside of the exhaust is dampened, the shell noise is reduced. So why is the power output affected? Logically it should be due to a change in the temperature or speed of the sound waves. The “tuned” function of the exhaust is based on certain variables and constants, and the residue on the inside of the exhaust causes the formula to change. The speed of the exhaust waves traveling inside the exhaust pipe changes, and so does the rpm at which the peak power is produced. Problem is, your clutching doesn’t follow this change in rpm.
What to do? We’ve heard of those who will, when the sound of the pipe changes, resort to cleaning the inside of the exhaust. How? We’ve heard of using a pressure washer, or using a spray solvent to loosen up and dislodge the goo inside. Anyone with experience in this area, please share your technique!