I was riding yesterday, when I noticed my speedo cable came loose from pod ( switched to the mini tach and speedo-months ago). I went ahead and placed back in but it still does not work.
As a last check disconnect the speedo end and rotate the front wheel, You should be able to see the end of the cable rotating slowly. If so the gauge is broken. If not then the worm gear is probably stripped.
Considering the price it must have some guarantee. At least a year I'd have thought.