Hi people. First thanks for all the advice on the recent purchase. All going great.
The Brake Light however is an issue.
The brake light comes on with the ignition (when lights are turned to off) and stays on when bike is started and lights are turned on. When lights are turned on the lower light in the rear comes on as well to illuminate the plate.
When I activate either brake, the top bulb increases in brightness slightly.

My question is. Should the top bulb operate at all apart from when the brakes are activated?
It passed it's WoF like this, but only just and it was a very dull day. The difference in brightness is not much.

Any help appreciated.

I am guessing that you are referring to the red lamp on the dash. This lamp should come on when the ignition is turned on but should go out after both brakes are activated. It is a rear bulb check lamp. After turning the key on, give both brake levers a quick jab, the lamp SHOULD go off. If it does not, firstly check the tail and brake lamp bulbs. If they are both ok and working, the next thing to look at are the brake lamp switchs, especially the back one, the early K rear brake lamp switch is notorious for getting water in it as it is quite exposed. Try sqeezing and releasing the front brake lever, then depressing the rear brake lever and flick your foot of the side of it so it springs back fast and hard, this sometimes works. If it is the rear brake lamp switch playing up there is not alot you can do about it other than replace it. Note just because it turns the rear lamp on and off does not mean it is not playing up) Any corrosion inside the switch will cause the dash lamp to stay on. The rear switch, front switch and the clutch switch are all exactly the same switch, so try the clutch switch on the rear brake t may solve your problem. The clutch switch is not as fussy about internal corrosion, plus being up on the handlebars it does not get the road grime that the rear brake lamp switch gets. The switchs are available through Motorworks at a reasonable price if you need a new one.

Thanks for that. It's the brake light at the back. It comes on with ignition and stays on with engine running.
After some research (on this forum) I've unplugged the rear brake light switch and the brake light stays on. So I must have a short somewhere. Either between the front brake switch and the electrical box, between the plug for the rear switch and the electrical box, or in the brake light warning unit itself? Any common areas this might happen?
Otherwise it's off with the side inner fairings and off with the tank again (one job I don't like as it always seems I want to do it just after I've filled it!).

Oh. The warning light comes on as it's supposed to and goes out with only the rear brake being activated. Front brake has no effect on warning light.

It should require both brakes activated to shut it off, perhaps it has been modified to only require the rear brake, that's good too, as long as it goes off all is good.

Process of elimination. It was the front brake switch. Used lots of contact cleaner pushing the pin in and out, then some crc to free it up. All good now. The back brake is still the only one to extinguish the warning light, I'm more than happy to live with that. Who would have thought so much black gunk could come of out of such a small switch and even smaller opening between the housing and the pin!!! Hopefully it will remain working, at least I know what to replace if it doesn't. Cheers