UPDATE: I got the bike started and can ride it around for a bit, but then it dies. It seems like when I play with the fuel hoses, trying to get any pinches out, that the bike runs fine. I got clear vinyl hoses for it, and when I put it to PRI, I can see the hose filling up. However, the hose does not fill up all the way (I dunno if it should).

When I'm riding it and just let out the throttle in 1st gear to let it idle, the bike really wants to die. It eventually does die, and I'm pretty sure it's because it's not getting enough fuel somehow. All of my lines are nice and straight......not twisted or anything. Once I set the fuel lever to PRI for a bit, the fuel hose fills up (almost all the way) and I can set it back to ON and ride for a bit. Then I have to repeat the process once it dies.

What could be wrong? Are my hoses just not working correctly?

Oh, I'd just like to add that the bike seems to run fine when I ride it in PRI. Would it hurt the bike to always ride it in PRI?

Going to work now.....just thought I'd bump this.  

What does it idle at? Maybe adjust the idle screw?

It idles at about 1200, which I believe is the correct setting....

1200 is correct. How does it rev in neutral? Can you grab a handful of throttle, snap it wide open as fast as you can (temporarily, don't sail past redline), and see what happens? If it doesn't bog, then your getting good carburetion down low and good fuel flow. Otherwise, I might second Davipu:

Quote from: daviputhen maybe a pinched hose, or a bad line/ connection on the vaccum line that connects from the petcock to the carbs

since your bike runs better in PRI (bypassing the petcock).

i think there are many gs's out there that only seem to run on prime.  when i got mine 2 years ago it was on prime and i havent moved it since. i tried plain ol' "on" a few times and the bike sputtered and died each time.  i just leave it on prime all the time.  doesnt overfill the float bowls and spills gas on the floor (at least on my bike)

doesn't prime flood the lines?
wouldn't it differ from "ON"

I am not really all that mechanically inclined... im just thinking outloud

ok, seems to be a vacuum problem in your (non tank mounted) petcock as in either a lack there of.

Vacuum is not connected if runs in prime only. Now vacuum being capped off at the carb isn't bad for the bike, cos it will not get free air making it lean ... but if bike has to be run in prime, please remember to shut it ... ON or res when you stop/park it ... else it will flood the floats.
Cool.
Srinath.

intersting reading - maybe it has a bearing on my problem (see High Speed Cutting Out - posted yesterday).  The vacuum pipe on my UK bike has a small plastic T piece halfway between petcock and carbs - should this line be one continuous line with no breaks ?