i've looked all over on my quad by the carb and i can't find the fuel screw. plus there are to many screws to know what i'm even looking for. any advice or help would be great. i've looked in all the forums and have found nothing that really helps me out. my quad is an '07 yfz450.

 

It's on the botton of the carb and is hard to see cause nothing sticks out. It's resessed in side. You will need a fuel screw tool or make your own. The best thing to do is replace the stock one with an adjustable fuel screw like one from MSR. It makes life simple to just be able to reach down and make a quick adjustment.
Do a search on google for fuel screw yfz and some where it will tell you more.