The doctor is in! Or at least it looks like he is in when the stethoscope from Graham Tools (part #52750, $25; www.grahamtool.com) is dangling around your neck. Many decades ago, savvy mechanics began using medical stethoscopes to detect the source of noises in cars and motorcycles. That was before a few tool companies started selling scopes designed for that specific purpose. For the most part, this one from Graham is typical of the breed in that it involves a long metal probe that not only transmits mechanical sounds but also is fitted with a small in-line diaphragm that magnifies them. This scope also includes a funnel-shaped amplifier on a long, hollow tube that lets you track down noises caused by air, vacuum and exhaust leaks.
When troubleshooting non-mechanical noises, you perform your Doctor of Motors act by first aiming the funnel in the general vicinity of the sound and moving it around until the volume begins to get louder. You then keep tracking that sound, following the increases in its volume until you find the source.
For mechanical noises, you touch the end of the metal probe to the general area of the bike that you suspect is near the source and, as with the funnel, keep moving it, touching other nearby parts until the sound starts getting louder. As you move closer to its source, the problematic noise becomes more distinctive and recognizable, making it easier to determine which components are most likely its cause.
Graham is not the only purveyor of diagnostic stethoscopes; many auto parts stores and tool suppliers also sell them, sometimes even at a lower price. But the quality of this one is a bit higher than usual, and most others include neither the rubber funnel nor its long extension tube that can access hard-to-reach areas.
