Tampering with motorcycle noise control systems is illegal in the USA
by Andy Ford, a founder of Maine Citizens Against Loud Motorcycles, Feb 28, 2010
The only way for a motorcycle to be loud is to violate laws, and loud motorcycles are often in violation of at least four laws. All motorcycles made after 1982 must have an Environmental Protection Agency noise compliance label attached to the chassis and a matching label stamped into the muffler [in the U.S.A]. It's a violation of federal law to re-place the noise-certified exhaust with one that isn't certified, or to tamper with the muffler in order to produce more noise. Under federal law, this information must be included in every owner's manual under the title, Tampering with Noise Control System Prohibited.
This section is very detailed and is very clearly worded as follows: "Federal law prohibits the following acts or the causing thereof; (1) the removal or rendering inoperative by any person other than for purposes of maintenance, repairs, of replacement of any device or element of design incorporated into any new vehicle for the purpose of noise control prior to its sale or delivery to the ultimate purchaser or while it is in use, or (2) the use of the vehicle after such device or element of design has been removed or rendered inoperative by any person." So there's no excuse for not knowing about it.
You may have heard the silly myth, Loud Pipes Save Lives. There is no credible study that shows that riding a quiet motorcycle is any less safe than riding a loud one. In fact, many thousands of bikers ride their whisper-quiet Honda Gold Wings safely every day. There are many proven ways to improve motorcycle safety; they include attending a safety class taught by a qualified instructor, installing daytime running lights, wearing highly visible, bright colored clothing, not riding when tired and not riding after consuming alcohol. The Harley Davidson Co. asks its customers to ride quietly, and the two largest motorcycle organizations, the American Motorcyclists Association and the Motorcycle Riders Foundation, also urge its members to ride quietly and respectfully.
In 2008, about 50,000 motorcycles were registered in Maine and the required annual safety inspection sticker was issued to only about 32,000. All other motor vehicles are required to display the inspection sticker and Maine Citizens Against Loud Motorcycles believes that motorcycles should also display the sticker. At this time, Maine bikers are only required to have the sticker with them.
All motor vehicles, including motorcycles, operated on public roads, are required to have a muffler. It's illegal to issue an inspection sticker to any vehicle that lacks a muffler or doesn't have an adequate muffler. Maine Citizens Against Loud Motorcycles (MECALM) believes that most of the bikes that aren't inspected couldn't pass because the machines don't have mufflers or have inadequate mufflers.
When the certified exhaust is replaced with an open pipe exhaust which has no muffler, such as drag pipes (which are legal only for off-road use such as racing and must be labeled as such), the air pollution equipment is disabled. This can result in one loud motorcycle emitting as much toxins into the air per mile of travel as 200 or more of today's cars. It's a violation of federal law to disable the air pollution equipment and is a Class E crime in Maine.