According to my old notes...

Non-Stock carb at DrATV (K2 - 1979)

Or, original Honda carbs have the following model numbers...

Late K1 -> K29A
K2 & K3 -> K29B
K4 - 1977 -> 556A
1978 -> B27A
1979 -> PB28A

And, you'll need to get the intake manifold and (I think) the insulator from a Late K1 - 1979, CT90.

Let's see if anyone can correct me... Maybe Neal?

Paved roads, just more needless government spending...

I pick up my mail in Santa Barbara, California, USA.