Frosty, congrats with your '76 550F1. Overhere, the early 550Fs were tested the most powerful of the 500/550 series. You must realise that up till then Honda only had to equip and set their carbs to create maximum performance and best driveability.
With the later 550K3 and 550F2 Honda messed up, to meet anti-pollution requirements in the USA and these models were reviewed accordingly here in Europe.
If yours has a 4-1, I see no reason why you shouldn't set the carbs like a 550F, even when they're stamped 627B. You can find data on p. 165 in the Honda Workshop Manual. I'm pretty sure the only differences between the 627B and 069A carbs are in the (removable) parts and their setting.
Can't really answer your question on the the air screws. All I know is, the 550F's had the solid tips, the 500 and 550K's had the drilled ones.
BTW, I'm still in the proces of trying to make sense of the confusing data I've seen in a spec booklet by Honda America Motor Company 1977. I don't know how to judge these carburetor settings as I don't know when and where what anti-pollution laws... I mean, was this just a Californian thing or was it federal?
