Hey gang,
Thanks for the info. So it looks as though I have a 2006 50cc Derbi. That helps. I've attached a few photos... as requested. Here's what I've been working on. I've been wanting to tune the carburetor. I found the idle speed screw and the air/fuel mixture screw. All the documentation seems to indicate that I should screw the air/fuel mixture screw in all the way, then back out the screw 1 3/4 to 2 turns out. THEN, start adjusting 1/4 turn in either direction until the highest RPM is achieved (then 1/8th turn clockwise to rich-en the mixture just a bit).
Well, first of all the bike has always run a little rough since I've had it (a month). That's why I wanted to do the tune-up. So today I got out my screw driver and attempted to screw in the mixture screw. Imagine my surprise when the mixture screw was already in as far as it would go. Besides it always smelling like gas and running rough, it's basically been running ok... especially at full throttle. Now, after I adjusted the mixture to where it SHOULD be (1-7/8 turns) it idles much smoother. However, sometimes at about half throttle it'll lag a little until I back off the throttle a bit. At full throttle it actually starts slowing down.
What did I do wrong? Should I have left the mixture screw turned in all the way? That do ya think gang?
~ Alan