It is a bit off topic but when I moved to Holland in 1989 from Germany I imported a T140V Bonneville from the UK.
Then you had to get a sort of MOT to get a Dutch registration.
The night before I checked the lights etc and the horn had failed (vibration & old age). The only horn I could get was a moped one which I guess was about 5 dBa.
At the test the guys were all motor bike freaks & loved the T140V. It had the tear drop tank & ape hangers a la officer & a gentleman.
They tested the noise of the exhust which should be under 75 dBa.
The Bonnie scored a secure 110 dBa. Which matched what I had tested the day before at work in Unilever Vlaardingen. The tester winked at me and said 73.
Then they tested the horn and fell apart laughing.
Happy days