Motorcycle Repair: CT90 Carb problem, air screw, float bowl

Question
I recently bought a 1969 K1b CT90.  It was a barn find, has 296 original miles on it (wow).  Needless to say carb was gummed up.  I've cleaned it, replaced gaskets and all of the other necessary restore duties to get it running for the first time.  This carb is the only year that it had the rubber float bowl gasket seating in the groove (may help Identify exact model).  As of now, I can start it first kick everytime. It will only start choke off.  It will initially run for 30 secs or so, that is while I'm giving it throttle to keep it from dieing, without throttle it dies.  It will not idle. I can restart it over and over, but only with giving it gas while kicking it over where it fires and dies in a second.  Air screw is 1 and 1/4 turns, Compression is full, is not flooding.  To me and other non-experts it seems its starving for fuel.  here's the kicker....If I let it sit for 30 minutes or so, I can start it and it will run for an extended period of time again (30 secs).  I'm at a loss. I've replaced all orings, blown out jets, so on so forth.  Any ideas or direction would help.  One more hint.  If when its running I try to choke it, it dies instantly, with choke I get no fire. Thank you for your time.

Answer
Cody, this a bit of a puzzle.  It sounds like it's not getting fuel or running out of fuel but it starts without the choke when the engine is cold which say's it's running too rich.  First, take the float bowl off and turn on the petcock and let fuel run out for a few seconds.  Make sure you have a good flow coming out of the needle and seat. If you don't, you may have a plugged screen in the petcock.  

Also check the float level to make sure it's not too high.  If the carb is running too rich the engine won't run well as it warms up. It may start, but it won't stay running.

Let me know what you find.

Regards
Rich