[pims]

Interesting, I had a look and it seems like it should be limited to 80dB for the biggest motorcycles. But that's when measuring in specific conditions in a lab, so there's a more "practical" (ahem) limit that depends on the model but is always at harmful levels (>80dB) and is measured when the engine is only at 50% of its maximum power.

So we have a badly designed law which is, as you mentioned, not even enforced. Sounds like France indeed.

[vladvasiliu]

I've looked a bit into it, and it's actually not that bad. [0] is a French source (not government affiliated).

Basically, as you said, there's the "official" test, which is dynamic (the bike has to be moving) and involved enough to not be practical for everyday controls by police.

But there's also a "static" test, for the purpose of facilitating police controls. The meat of it, from the article, is below. The parameters for this test are given on the registration slip of the vehicle (expected sound level / RPM).

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The sound should be measured with a microphone placed as follows:

* At an angle of 45º to the vehicle's longitudinal axis

* At 50 cm from the muffler

* At the height of the highest point of the muffler and at least at 20 cm from the ground

* If the bike has mufflers on both sides, testing should be done with two microphones, one on each side

Testing conditions:

* Testing must be done at 50% of the nominal power RPM [not max RPM]

* If max RPM is 5000 or less, testing must be done at 75 % of nominal power RPM

* There must be at least 3m of free space around all sides of the vehicle

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This level is higher than the one in the official test, but it doesn't really mean anything. The official test is done wide open throttle starting at 50 km/h, so it should reflect fairly well the actual noise produced when riding around town. The static test isn't involved in the homologation of the vehicle, it's just there for the police to be able to check that the vehicle hasn't been tampered with.

[0] https://ffmc.asso.fr/bruit-des-motos-comment-le-mesure

[pims]

Thanks for clarifying. Given the considerable amount of motorcycles that are way too loud, it still feels like the noise limits for homologation are way too high. Or if that many bikes have been tampered with, it means there really is absolutely no enforcement whatsoever. Either way it sucks :/