ACEM, the European Association of Motorcycle Manufacturers, has produced a new set of guidelines designed to make it harder to remove baffles or other noise-reducing parts from type-approved aftermarket exhausts. The aim is to reduce noise complaints about motorcycles caused by end users altering their exhausts, particularly by removing “dB Killer” outlets or other mods.
The rules, aimed at aftermarket firms, recommend that baffles be permanently fitted and unable to be removed with everyday tools without cutting, drilling or grinding. Welding, glueing, steel rivets or break-head bolts are all recommended, and the guidelines also say that removing sound-reducing parts should cause permanent/irrecoverable damage to the assembly.
Announcing the new initiative, Antonio Perlot, ACEM secretary general, said: “This initiative, bringing together the expertise of recognised players in the motorcycle sector, addresses one of the main causes of motorcycle noise in the streets. Approved silencers with too easily removable baffles or dB-Killers are today still present on the market, which may result in unacceptably high levels of noise on the road.
“Putting forward state-of-the-art solutions, the guidelines will help type approval authorities towards a more harmonised assessment of conformity to anti-tampering rules for exhaust silencers. The call is now on all stakeholders to apply them without delay.”
The recommendations are aimed at road-legal pipes and won’t affect makers of race exhausts and non-type-approved parts.
The full recommendations are available online at: unece.org/sites/default/files/2023-01/GRBP-77-20e.pdf