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Message: [QUOTE="Tony Eeds, post: 1184816, member: 32023"] Dave: There are VERY specific rules and criteria that must be followed to accurately determine the dB rating of a bike. It is not accurate to say that a bike measuring 98 dB would be quieter than a bike measuring 96 dB, unless the testing procedures are not followed. To test a bike the sound meter must be 20 inches and 45 degrees from the exhaust tip and the RPM at 50% of the RPM at max horsepower ... or torque ... I've forgotten which at the moment. Check out the RPM chart [url=http://www.chemhelp.com/][i]here[/i][/url] to learn about your particular bike. Chris Real and his partner are heavily involved in the sound issues. His partner (who's name escapes me at the moment) wrote the rules (SAE J1287) that we follow when determining the noise generated by a motorcycle in a static situation. This is the source of the 96 dB requirement that many people reference. [url=http://www.motorcyclenoise.com/?&MMN_position=2:2][i]Here[/i][/url] is a link to their motorcycle sound website. You are accurate in saying that the tests cannot likely be duplicated over a long period of time on the same machine, but the reason is related to the type of exhaust system. Generally speaking, after market exhaust systems rely on packing that deteriorates over time and a machine with maybe 20 hours of time on the packing will not match it's own results with fresh packing. Indeed, 20 hours of run time can easily be the difference between legal and illegal. If you get stopped for sound measurement by a ranger and he issues you a citation, be sure and collect the data related to the sound meter used, the method and the range the meter was set on. Also follow up and ask for the most recent calibration info on the unit when you get home. Not every unit made is usable for law enforcement. It must be a Type 1 meter, to be admissible in court. Sound is a HUGE issue and, by far, the most talked about subject at the recent NOHVCC conference. Please keep your machines at or below the 96 dB rating. I am leaving the stock exhaust on my DR650, as it is well capable of scaring me in the stock configuration. There is zero connection between the level of sound that a machine makes and the horsepower output. As a final thought ... if loud pipes save lives, why don't pipes face forward. [/QUOTE]

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