If this is for a Yo, then buy the Gripnut. If you can get it for £65, its well worth it Been meaning to get a King for the C40, but can't justify junking the perfectly serviceable Campag Record
I had the same problem (although not on a Yo ) I ended up switching forks and using a cartridge job until i found a shimano road headset to nick bits off
This post doesnt help much does it? :? still at least you know your not alone!....erm....i'll get me coat.