EBAY is your friend for stuff like this. Actually, if you want to be sure, go to your local hardware store, buy a 5mm and 6mm screw, and see which one fits best. Start with the 5mm. Re-Run is most likely correct.
Hope it helps.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.