The car has been running a bit rough of late,with a petrol smell coming from the bike carbs. So i thought i'd change the main jets for smaller one's ( old ones were to big), bugger me one jet had fallen out and laying in the float bowl !
Has it happened to anyone else?

No, what carb? Could it have been knocked out by a backfire?

Though it has to be said better in the float bowl than in the cylinder

zx6r carbs. never had a backfire. must be the only thing not locktight, nylocked, welded or glued.

It does'nt happen often but it does happen

I had a drain plug fall out and chuck copious amounts of fuel onto the hot engine (and masses of fuel vapour into Welly's face as he was following me round Langbaugh circuit at the time!).

I just put it down to the vibration and the plug being just a little loose is all. Tightened up correctly and never had a problem again.

I had a jet vibrate loose and meant the float only went halfway up the bowl so the engine was fine cruising but as soon as you put your foot down or at high revs the fuel was soon used up and the engine would struggle.