HRS §291-24
Noisy mufflers on motorcycles and mopeds
This law requires motorcycles and mopeds on public roads to have working mufflers that keep noise down. You cannot modify the exhaust to make it louder, except for certain three-wheeled, electric, or fully enclosed vehicles. Violating this can cost up to $150.
everyone
The statute, as written — Motorcycles and mopeds, noisy mufflers; penalty
(a) Every motorcycle and moped moving under its own power on a public highway shall at all times be equipped with a muffler in constant operation to prevent any excessive or unusual noise and no such muffler or exhaust system shall be equipped with a cutout, bypass, or similar device. No person shall modify the exhaust system of a motorcycle or a moped in a manner which will amplify or increase the noise emitted by the motor of such motorcycle or moped above that emitted by the muffler originally installed on the motorcycle or moped except a motorcycle or moped that: (1) Has three wheels; (2) Is powered by an electric motor; (3) Has a full body enclosed cab; and (4) Has a seat belt assembly or a child restraint system for the driver and passenger; shall not be required to be equipped with a muffler. (b) As used in this section, "muffler" means a device consisting of a series of chambers or baffle plates, or other mechanical design, for the purpose of receiving exhaust gas from the engine of the motorcycle or moped, and being effective in reducing noise. (c) Whoever violates this section shall be fined not more than $150.
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