is just for adjusting the air fuel mix at idle. It controls the fuel. If you set it at 2 1/4 turns out from lightly seated, it should be fine. I'd do that, and then not mess with it, until the bike is running well. IMHO
, if you set it there, it will be fine forever. That's where the factory sets them.
The proper float level on these bikes, is about 4mm above the bowl to carb
mating surface. This is checked by Yamaha, with the carb on the bike. The bike sitting upright(it works best on a bike stand(lift)).
Attach a small clear tube to the bowl drain, and open the bowl drain screw. The fuel will fill the clear tube, to the level in the bowl.
***Now then, the fun part....you want to hold the tube vertical, along the rear(the intake manifold side, not the air cleaner side) edge of the carb. It'll come off the bowl drain, loop around and up along the back(intake manifold side) corner.
Be advised, as long as the petcock is open, the tube is on the bowl drain and the drain screw is open, if you let the open end of the tube get below the fuel level in the bowl, it'll promptly drain the tank, and in the process pee fuel everywhere.
If you get north of between 5 and 6mm, you'll be getting into a possible rich scenario. Over 6, and it may run but you'll foul plugs after a bit. 4mm-ish, should be just fine.
Don't over tighten the bowl drain screw. You can crack the seat area. Snug is good.
Cap the brass nipple on the intake, if you haven't done that yet.
If you haven't noticed already, there is a "Tech Articles" tab above. click on it, and it will have a lot of carb stuff to look at and read, that pertains exclusively to the Roadies.