... some times it takes a certain amount of pressure to present its self. If you just pump the bladder up, outside the kite, you won't get enough pressure for the little hole to leak and show up.
Put the bladder in the kite, pump up to pressure, ie say 6 psi then get a spray bottle with dish washing liquid in it and spray the kite, starting with the valves, then check the ends and if you still don't find it, spray the whole thing.
You'll see bubbles, take note where the problem is then take just that part of the bladder out and locate it again, but this time you have a better idea where it is. Spray the dish washing liquid on again and run your finger over the bladder really slowly til you find it and make sure you have a pen on hand to quickly circle the hole so you don't loose it.
Patch the hole and fit bladder back into kite and your done.
Hope this helps,
Robbie
ps, I bet its a valve thats gone
