Don't ask me how. I have just bought the sweetest bike, ckt carbon track bike, for a steal, When I got it home I noticed the ahead cap bolt seemed overly large and protruded out alot. When I removed it inside was as expected a star nut (only about 10mm 1/2inch below top of aluminium steerer carbon fork) and below this star nut is another star nut with a cut off cap bolt driven to the bottom of the steerer tube. How do I remove it? or do I leave it and buy a new star nut and proper sized cap and bolt combination. I read in another thread here that you can drive them out from the bottom with a dowel but the inside of the steerer tube looks chewed to peaces, as if some one has been trying something.
Don't worry, I got it out, I tried driving it out with a dowel and a soft face hammer, with little change, I then changed to a flat bladed long screwdriver and a 3lb hammer, the sprung steel of the star nut shattered and it simply fell out. No damage to inside surface of steerer tube.