Too Darn Hot!!

Can't sleep co's it's too darn hot even the wind outside is like standing in a hairdryer and it's too late to go for a blast. So Ouzo and lemon in hand I visit the Garage.....................

Standing by the bike I can hear hissing from the tank - obviously fumes and air pressure involved but I was also wondering as I have a carbed model is there a natural leakage through the carbs when left standing as I've never bothered to turn the tap into the off position before and when I did - tonight, the hissing stopped?

Just for the record I couldn't smell any petrol and there isn't puddle anywhere near or on the bike.