@JimmyT said:
…If the bike turned out to be a de-muffled Harley-Davidson…
When I am not being a strata guru or hifi nerd I am an electric vehicle enthusiast. So, I have to point out that I see nothing wrong with this de-muffled Harley: https://www.drive.com.au/motor-news/we-ride-harleydavidsons-electric-livewire-20140909-10ecb7.html and https://projectlivewire.harley-davidson.com/en_AU
But, yes, I agree that permission could be given subject to the condition that it can be revoked if there are significant, substantial and repeated complaints of nuisance from bring the bike over common property.