Float Level Problem

Hey,

So I've got my carbs on a bench, bench synced, now I'm trying to do float levels. The carbs are level, fuel line is attached from petcock to the carb inlet and the tank is elevated above the carbs. Another fuel line is attached to the float bowl nipple. Now, when I open the float bowl drain screw and set the petcock to prime no fuel flows whatsoever. It's as if there some sort of pressure resisting the escape of air to let the fuel in.

I've decided I must be doing something stupid. I've checked the petcock without the carbs, flows like normal. I've taken off the bowl and let fuel flow, flows fine and is stopped by the floats rising if I use my hand to simulate so there are no obstructions to fuel flow. The problem only arises when I attach all the bowls in a sealed system.

What's going on? :?:

 

Maybe? I dunno - perhaps it's real simple --

You may "think" you've set it on PRI, but you've set it to RES -- swing the petcock arm all the way on the other side -- the "handle" has to cover the letters "PRI" -- It threw me when my bike was new

 

This might be obvious, but are your float bowls clean? It sounds like there might be a blockage at the bottom, if fuel is flowing just fine with the bowl off.

 

Your floats aren't upside down, are they?? I can't remember right now if that is even a possible cause of your problem with these carbs, but I believe we've seen it before in other carb types.

P.S. Are the carb vent lines open? (Not capped off or whatever?)

 

Oh it sure is (upside down floats.)

 

Thanks for your investigative work! Upside down floats! Case closed!