Brake light not working

I have recently purchased an 81 KZ440 and noticed that he brake light only works when the rear brake is used not the front. Surely this can't be normal. Can anyone give me an idea of how to fix this?

I think on your model of bike, there is an electrical connection on/under the master cylinder. Make sure the connection is good there.
From there you might have to trace the wire back through the harness and check for continuity.