Thank you for the information.
I grabbed a pair of calipers from work and you are correct, the new parts (2NX-12159-00-00) are 6MM. However, the current screw in my bike does measure out at 7MM (6.9342MM exact). The locking nut has an inside dimension of 6.223 MM.
Any suggestions as to referencing the various Yamaha Valve Adjustment screws to their respectives sizes. Even a phone number to an actual Yamaha dealer anywhere in the States that may have a hardware reference manual. I have called several "Yamaha" dealers in florida but they are all multi brand dealers that only have access to the standard mirofiche files that we all have seen.
Any help would be greatly appreciated as the busted adjustment screw is slowly wearing down thought the threads now, the compression nub is what has broken off. I ride the bike every day to work and have to re-adjust the valve screw every 40-50 miles. I would like to avoid replacing the rocker arms as I don't have the time right now to rebuild the top end nor the funds and I depend on the bike to get to work.
Thanks