I had a mystery solved today...
The past few weekends I have been woken up by what sounded like someone mowing the lawn with a petrol mower. I would look out of the window to try and see who it was, nothing. Just kids playing on their bikes in the street.
This morning, I realised the noise WAS one of the kids! Does anyone know what this is? My grandad told me about a device called "King of the Road" that was a small petrol engine to strap to a bike, but I can't imagine this is what I am hearing as the kid is about 9 years old. Is there some kind of motorbike sound-effects unit that measures the speed of the bike? Only it does seem dependent on his speed!
Whatever it is, it's bl**dy loud!