When I had to get a new tube in a hurry at the tri on Sunday because my rear tire had exploded on the rack ( really more like a loud pop, but still), the woman from High-Tech Bikes who changed my tire inflated the new tube by mouth about a third full before slipping it around the tube, She said it made it easier to handle.

I've not had a lot of luck inflating my presta valve tires, either. I've had the same problem with the poor seal, so I reset the valve and when I pump, the pressure gauge is all over the place, which is why I overinflated the tire Sunday. I saw 130 on the gauge,
but it was obviously a lot higher.

Roxy