The Society of Automotive Engineers International has developed a sound test standard for testing motorcycle exhaust systems for excessive noise.
The J2825 “Measurment of Exhaust Sound Pressure Levels of Stationary On-Highway Motorcycles” standard sets testing conditions, procedures and instrumentation for measuring sound levels.
The need for a sound testing standard was a top recommendation of the 2003 National Summit on Motorcycle Sound. The AMA-organized summit gathered ideas from riders, motorcycle manufacturers, aftermarket industry representatives, racing promoters, government agencies and others on how to address the issue of excessive motorcycle sound.
Ed Moreland, AMA vice president for government relations, says noisy exhausts create negative stereotypes about motorcycles, and J2825 will help local jurisdictions set reasonable limits.
“The motorcycling community and law enforcement have long sought a practical field test for measuring street motorcycle exhaust sound,” says Moreland. “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.
“The AMA maintains that few factors contribute more to misunderstanding and prejudice against street riders than excessively noisy motorcycles,” Moreland continues. “With the new SAE J2825 standard, street motorcyclists can now determine how quiet, or loud, their bikes really are.”
The SAE J2825 test is similar to the SAE J1287 test used for off-road motorcycles. A calibrated sound meter is held at a 45-degree angle 20 inches from the exhaust pipe of a running engine. J2825 establishes how to test the sound level when the bike is idle, at a predetermined engine speed (“Set RPM Test”), or by slowly increasing the engine speed (“Swept RPM Test”).
The SAE Motorcycle Technical Steering Committee recommends a limit of 92 dBA for all idling engines. In Set RPM or Swept RPM tests, the recommended cap is 100 dBA for three- or four-cylinder engines, and 96 dBA for engines with less than three or more than four cylinders.
While the AMA supports the J2825 standard, Moreland says other sources of excessive noise should face the same scrutiny as motorcycles.
“The J2825 test allows jurisdictions around the nation, struggling with complaints about excessive motorcycle sound, to set reasonable limits in accordance with the SAE standard,” says Moreland. “While the AMA supports the establishment of the SAE J2825 standard in America’s cities, towns and communities, we will continue to fight efforts that single out motorcycles while still permitting excessive sound from other sources, such as loud c
