Approx how many decibels is a moto gp?

Question

running at top speed? e.g. an f1 car is about 127 decibels

Answer 1

115 before the race, and no more then 135 at the end.

It was in 2007, I dont think it has changed for this year.

Answer 2

I don't know the answer to this but may help with the working it out. I don't follow F1 anymore. (cant stand watching parades)

But as I remember it F1 were running 3litre v10 engines that's 300cc per cylinder

the big 900cc 5 cylinder bikes run at 180cc per cylinder

The 800s will be even less

As the noise is the sound of the explosion in the exhaust pipe

and the explosion is almost half the size it should be around half the sound.

this equation does not make sense to me as i have heard both and there is not that much difference. the car exhaust is almost vertical and is shorter than the bikes, this may account for some of the reduction in noise on the bike. i must admit your figure for the car sounds bit low to me. I would have guessed at the bike putting out around 140-150 Dcb and an F1 car doing around 180Dcb

You could always google for an answer.