I came across a problem I have not met before. Trying to check the pressure in Wendy's scooter tyre, the separate tyre gauge would not register at all and the pump gauge registered max (ie 100ppsi) on the first stroke of the foot, but clearly would not put air into the tyre..
Investigation showed that something was lodged around the pin of the valve. I finally extracted the blockage with a piece of fine wire bent in a hook.
It turned out to be a small rubber seal from the top of the cheap plastic valve cap. It was obviously intended to be a second seal against air escape, but became detached as the cap was screwed down hard, and jammed around the pin of the valve. Difficult enough to see and extract in the workshop, but I suspect it could be a bl---y nuisance if you were trying to top up your tyres at a garage.
Perhaps it would not happen with a quality metal cap (I have at least one on any bike with a valve extractor top) but examination of some cheap plastic caps showed all had loose or detached rubber seals.
Investigation showed that something was lodged around the pin of the valve. I finally extracted the blockage with a piece of fine wire bent in a hook.
It turned out to be a small rubber seal from the top of the cheap plastic valve cap. It was obviously intended to be a second seal against air escape, but became detached as the cap was screwed down hard, and jammed around the pin of the valve. Difficult enough to see and extract in the workshop, but I suspect it could be a bl---y nuisance if you were trying to top up your tyres at a garage.
Perhaps it would not happen with a quality metal cap (I have at least one on any bike with a valve extractor top) but examination of some cheap plastic caps showed all had loose or detached rubber seals.