I've been doin some reading on this subject and here is current state of affairs for NH:
Chapter 266, Equipment of Vehicles, Miscellaneous, Section 266:59-III
No person shall modify the exhaust system of a motor vehicle in any manner which will amplify or increase the noise emitted above that emitted by the original muffler installed in the vehicle and such original muffler shall comply with all the requirements of this section.
Section 266:59-a, Motorcycle Noise Levels
I. No person shall operate a motorcycle which has a measured noise level of more than 106 decibles on the decible meter when measured 20 inches from the exhaust pipe at a 45 degree angle while the engine is operating at 2800 rpm for one and 2 cylinder motorcycles (3500 rpm for >3 cyinders).
II. No person shall pass for the purposes of the inspection required by RSA 266 (exceeding the above).
III. No person shall operate in this state any motorcycle which produces a sound level in excess of 106 decibles on the A scale, when measured in accordance with the provisions of the Society of Automotive Engineers Recommended Practice ANSI/SAE J-1287 annual report on "Measurement of Exhause Sound Levels of Stationary Motorcycles."
IV. Any person who violates the provisions of this section shall be guilty of a violation.
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Topic: State of NH Regulations MC Mufflers (Read 9673 times)