I have a 2001 yamaha v-star 650, i can start it up by pulling the choke all the way out, then let it warm up, push the choke in a little and it still runs, but if i push it all the way in, the engine dies. also, if i try to roll on the throttle when it is idling with the choke out, it dies. i was wondering if it might be the fuel pump going out or what. i have tried running it with the air filter off to know that it is getting enough air, and i have tried adjusting the idle, no help either way

SOURCE: how to lower the idle on a 2002 yamaha 650 v-star classic?

under the left side of the gas tank you will see i black knob/screw at the end of what looks like a hose. the knob faces the rear of bike. that adjusts the idle. its real easy to find and the only adjustment you can make to the carbs.

SOURCE: 1982 Yamaha Maxim 650 Has

These bikes need the carbs ajdusted rather frequently, once they get out of adjustment the they juste don'e idle good. Also as old as this one is I can guess that you may have some air leaking around your some of the gaskets and this is why after it warms up it runs better, the gaskets get heated and the swell a little and then start sealing better. It would do you good this winter if you replaced all your intake and carb gaskets and get the carbs adjusted by a trained technicianan you will be ready to roll when summer comes around.

SOURCE: Lost of power on throttle increase and motor dies

I would say you have a blocked or damaged jet. I would strip down the carburettor and replace any badly worn jets and clean thoroughly. When refitting the tick over mixture screw , screw it home and back out about 2 1/2 turns. That will be somewhere near it.
Hope that helps.

SOURCE: How do I adjust my

Follow the link, part # 4 is your idle adjustment screw. It is located under the carbs.
http://www.mrcycles.com/fiche_image_popup.asp?fveh=28600&section=1050744&year=2009&make=YAMAHA&category=Motorcycles&dc=792&name=CARBURETOR