The speedo on an VFR400 is driven off the front drive sprocket, check the cable and the nylon drive down at the engine end,I dont think it will be the drive in the clocks.
Take the cable off the bike and make sure the nylon drive is turning the drive at the clock. if not you need a new cable.
the nylon drive end fits over a not on the spocket check this is not cracked and gives drive.
If the clocks are away you might be better getting a second hand set. If you want to repair the clocks let me know and i'l talk u thru it cause i've the genuine Honda manual 4 this bike, and Honda still supply all the parts for VFR400.
Good luck
Busa boy
March 2008