Why does the gas light flash on and off with a full tank of gas

The light flashes when you are going low on fuel (1 gallon left IIRC), and a solid light means get fuel now (1/2 gallon left). Now, if you have a full tank (i.e. > 1 gallon), and it is still flashing, the problem is most likely a stuck tank level float. Try unplugging the fuel unit connector and see if the light goes out. If it does, you have a problem in the level unit (i.e. sender/float). If it doesn’t the problem is in the cluster or the wiring harness.

I’ve heard of this problem occurring after the bike has been stored for the winter with an semi-empty tank of gas, and the float gets stuck. Some people pull the fuel pump and clean the float. Others have reported that they just keep driving, and the float will eventually become unstuck and work as normal.