yep, nope not cutoff valve. that one is shorter, fatter, tougher, all kinds of "ers"..
I remember dealing with it last time, definitely exterior of carbs, really think it was part of the enrichener levers....there's a plastic washer there too, and i can't remember where it went, but since no one else is responding, i'm assuming that it is not needed.....
carbs all put together, sync systems hooked up with each other, and enrichner linkage working swell.
tip for carb re-assembly, keep the brackets "loose" on top til hya make sure the choke linkage working properly, then tighten up. i had the carbs skewed a bit and the enrichener choke wouldn't work cuz the lever arm off the linkage to the enrichener was binding up against the enrichener pull out part...the carb wasn't str8 enough...
anyways, putting carbs in bike after work. i have a ****** battery, but it'll be juiced up enough to see if bike will start....
i will take video and youtube upload and share link afterwards.