I think I got my answer from the Carb Theory 101 PDF.  It seems from that reading that it is just the taper of the needle that effects the ammount of gas that can be drawn in.

Probert31 wrote on 12/31/69 at 16:00:09:


Did you put the small spring back in the needle assembly??

I assembled the needle assembly as shown in the tech diagrams.  After I tightened down the two screws on the plate that holds the needle in, the needle did not move.  The spring is under it but there really isn't much motion anymore.  I replaced the white spacer with two brass washers.  When I tested the needle in the white spacer, it was tight enough that there wasn't any give there either.  I am having problems, as I already put it back in.  The bike runs fine with the choke out, but stalls at 1/4 throttle with it in.  It gets worse as the bike heats up.  I just figured I had to tune it better.  Just to make sure we're all talking about the same thing, the needle has a spring, washer, clip, then the white spacer on it.  I put this into the hole on the diaphragm assembly then screw it down with the little brass plate and brass Screws.  At this point, there wasn't much "up and down" give on the needle itself.  I remember taking it apart and having it move in and out of the assembly but I figured that was because I had loosened the screws.  So, the needle should move freely in and out of the diaphragm assembly under the brass plate holding it in??