I ride an 2003 cbr600rr and recently the fuel gauge on the cluster stays blinking all crazy like full and then empty and then mid even when i have a full tank of gas so i was wondering if anyone knows anythin about this or if this has happen to someone ?

 

Check the earthing/grounding on the tank sender unit - if it's intermittent, that would cause your problem. A partial break in the live wire would do it too, so check for continuity on both wires - they sometimes break inside the coating ,,,,,,,,[X(]
Only other cause could be a faulty sender unit, but I suspect the earth wire...
Hope it helps.