Running lean


I recently got a new bike an 03' yz250f, lovin it, but its running a little lean. Unfortunately I didn't get an owners manual with it. I tried looking at the carb last night so I could lower the clip to run her a little richer but I couldn't exactly find the needle and clip. I took off the top lid of the carb but didn't find what I was looking for. Any help with a diagram or where to look or a quick "how to" would be great. Sorry for the dumb question guys but I'm used to two strokes, this four stroke is throwin me a little. I appreciate any help.