for Honda Z650 year 77-79 with original Mikuni carburetor
Keyster = KYV-03020
OEM =OEM = 16030-1002
OEM = 16030-1001
please check and adjust float valve level if you chang float valve.
level data you find by Keyster carburetor parts in this shop, search your model.
please clean your petrol system
change complete set, not only new valve in old holder.