Did oil change, no speedo.. WTF??

[bigjay]

Hey guys what would i need to look for to find a fault with a non working speedo? When the key is turned it moves from 0 to 300 and back so its not the dash. The sensor is tightened in the sprocket cover. All the plugs are where they are supposed to be. I'm at a loss..... All this from an oil change which is done on the right side of the bike. Go figure!!! By the way, its an 03 busa.
THANKS GUYS