I just took my tank off to clean the plugs and noticed that theres a wire that comes from the main loom that runs down the right side of the bike just blow the tank that connects to a wire coming from a bolt to the side of the coolant cap. I smelt a slight burning the other day & apparently this wire is the reason as its melted right through the plastic to bare wire.

Does anyone know what this wire is for???

There are 4 other wires coming from roughly the same place in the loom that run the cooling fans either side, as they come out in pairs so im sure i havent connected the wrong wire up so its got to be another reason its getting hot. As far as i can see the bolt its connected to thats near the coolant cap is just a fixing bolt, so it must be an earth for something so i dont reallt get why its getting hot.. any clues??

Do you know what colour it is/was?

Black with a white stripe, the same as the earth wires for the fans. I've disconnected it so it cant keep shorting out but it hasn't seemed to effect anything, all the electrics are working fine still so im completely stumped what its for at the minute lol

Your right it is a ground wire. It's to provide ground to the coolant temp sensor, and thermostatic switch for the fans. The thermostat housing is still grounded through the frame, so that's why everything still works.

For a ground wire to melt it would have to be shorted to 12 volts (most likely to be shorted to the fans black/brown).

I would open up the harness where the wire comes out and take a look for any shorts!