How do you inflate a racing cycle tyre?
remove the plastic dust cap, unscrew the tiny knurled nut until the valve centre pin can be pushed in, you will hear air escape if any in tube, before fitting the pump adaptor, give the nut a final outward screw to tighten it against the end of the pin, this stops it being screwed in again as you fit the pump adaptor, inflate to recommended pressure, remove adaptor carefully to prevent deflation and tighten nut, pulling outwards slightly as you do so, refit dust cap.