I KNOW its a bit, er, loud!
I have such memories of watching one being warmed up in a certain hotel car park, in Douglas, by little Honda mechanics in white overalls and gloves. The six was revved up and the needle went most of the way around the dial. This was accompanied by showers of pebbledash falling off the hotel wall! Awesome.
Another, slightly later, memory is of coming up alongside Ago and Magni on two of the MV 3s at the traffic lights on the prom, on the way to morning practice.

More recent memories are of the Fath URS fours (solo ridden by John Blanchard and outfit but Colin Seely) at Scarboro. I was in the top car park and the sound from down at the start (!) was amazing. But..when they came up to the top? I guess I could sue!! Lovely stuff.
Finally, 2 years ago, I was at an MV gathering at the Sulby Glen Hotel (are those gatherings gone for ever?)
In among the relatively modern 750s etc , was a GP 350 four. The owner (or rider?) produced a roller to start it up. Those of us who knew what to expect, either move away slightly or put fingers in ears! The younger ones didnt do either and got one hell of a shock!!
I have to say, I miss the noise in the Island but it sems to be back in MotoGp!

Mike