Re: Carb/throttle needle valve adjustment
Second notch from the top is a good ball park starting point. As suggested above, after a few miles, a couple of tanks of fuel, check your plug. Very dark indicates a rich mix at which point you might consider raising the 'C' clip a notch but only after a few miles. Two or three tanks of fuel will tell the story better than just a tank full. Don't be afraid to twist that throttle either. Run it hard a few times; it won't hurt your engine and will reduce the break-in time. Running too soft for too long will not help a thing and can keep the rings from setting properly. They're tough little motors and like a little abuse.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"