I've built a home CO2 carbonation system but I have a question about carbon
dioxide flow (see pictures below).
http://yfrog.com/13homec02system5jx

Using a tire valve and a tire chuck, I can easily fill the soda bottle
empty space with 50 psi of carbon dioxide, but that only gets the water
slightly bubbly.

The build-it-yourself tutorials on the web say the carbon dioxide must be
FLOWING and they say they remove the inside part of the automotive tire
valve.

I have tried both ways and have two subsequent questions:

If I keep the tire valve stem (i.e., the white soda top in the photo):
Q: Why doesn't the cold water get more bubbly (like soda) at 50psi?

If I remove the tire valve stem (i.e., the red soda top in the photo):
Q: How do I get the tire chuck to work since it won't flow w/o the stem?
Q: Even if I attach the hollow tire valve directly to the CO2 hose, how can
more than the headspace of the bottle FLOW into the bottle?

I don't get how I can get the CO2 to "flow"; seems to me it would just be
static and fill the headspace.

What am I doing wrong?
See pictures he http://yfrog.com/13homec02system5jx