Although tampering with motorcycle exhaust systems has been illegal since the 1970s, the federal mandate has been mostly ignored by law enforcement until recent years. The reason for the renewed interest in the law stems from a dramatic increase in the number of citizen complaints about loud bikes.
While the non-riding public thinks most motorcycles are too loud, a majority of riders who purchase new bikes exchange the stock exhaust systems for after market products that increase performance as well as the decibel level. This is true for not only Harley riders but many of the sport bike riding crowd as well.
Some of these same riders, including me, believe that a louder than stock motorcycle helps us become more conspicuous on the roadways, not in an offensive way but in a self-preservation way. Stock motorcycles are hard to hear by car drivers who have their windows up and radio blasting. A simple blip of the throttle can alert a driver that we are coming alongside the vehicle.
The increase in complaints from the public stems from some riders who think obnoxiously loud bikes are better. Practicing throttle control can dramatically decrease the sound level of a bike while cruising through urban neighborhoods. The problem is a number of riders are so in love with the sound of their exhaust that they don't consider the irritation it causes to non-riders trying to relax in the quiet of their home.
Check out the link to read more about this issue and view a video interview I did with a columnist for the Milwaukee Journal Sentinel who focuses on motorcycle issues. Meanwhile, the motorcycle rights community urges riders to control the sound of their motorcycles to avoid being cited individually and to also avoid the bigger problem of increased noise level restrictions and regulations.