The Society of Automotive Engineers (SAE) International has produced a simple, consistent and economical sound test standard that can be used to determine whether a streetbike (on-highway motorcycle) exhaust system emits excessive sound, the American Motorcyclist Association (AMA) reports.
The J2825 "Measurement of Exhaust Sound Pressure Levels of Stationary On-Highway Motorcycles," issued by the SAE in May, establishes instrumentation, test site, test conditions, procedures, measurements and sound level limits. According to the SAE, the J2825 standard is based on a comprehensive study of a wide variety of on-highway motorcycles.
"The motorcycling community and law enforcement have long sought a practical field test for measuring street motorcycle exhaust sound," said Ed Moreland, AMA vice president for government relations. "Thanks to the hard work of the Motorcycle Industry Council, and the SAE engineers involved in the project, for the first time a simple field test is now available.
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"The AMA maintains that few factors contribute more to misunderstanding and prejudice against street riders than excessively noisy motorcycles," Moreland continued. "With the new SAE J2825 standard, street motorcyclists can now determine how quiet, or loud, their bikes really are."
Moreland added that the new standard follows a template established years ago with the SAE J1287 off-highway motorcycle sound test, a standard recommended by the AMA wherever off-highway motorcycles are operated.
The SAE J2825 on-highway motorcycle sound test procedure is similar to the one used for the SAE J1287 off-highway motorcycle test. The streetbike measurement requires holding a calibrated sound meter at a 45-degree angle 20 inches from the exhaust pipe of a running engine. The procedure spells out how to do the test with the bike at idle, at a predetermined engine speed ("Set RPM Test"), or by slowly increasing the engine speed of the bike, known as the "Swept RPM Test."
