These bikes were offered for sale in the 60's by Valintines Army Surplus, Hamilton, N.Z.. They were built from all new army surplus parts.
I'd had the carb apart and was having persistent flooding. The ultimate solution was simple. Loosen the screw holding the float and move it in the slot, away from the needle valve. The slot itself is only a few millimeters but that's all it needed.
Pic below is testing the float and valve. I used a cork to plug the hole.