Carb just got here from BGF, I think it took 3 days? It came with a black version of the NT filter, it has "HB" on the side, and the carb looks IDENTICAL to my speed carb. Externally they are definitely the same sans a few supplier differences. I'm inclined to believe the NT, speed and this HB carb are one and the same.
As far as the bore, it's the same as every china-girl carb. They have to all fit on the same intake pipe, yes? Idle-needle; No china-girl carb has an idle needle. Only the CNS carb has one but the CNS carb is NOT a china-girl carb
, that's a 50cc pocket-bike carb. That's why it never fits right and has those extra unused nipples; those go to vents on the tank/intake/etc. It's prolly also why you guys have so much trouble tuning them.
And as an added bonus, BGF includes an o-ring to seal the intake to the carb.