I took my Supersport for it's first Mot this week the tester commented that number plate light was very dim. I had a look at it today and found the one of its 3 LEDs has failed completely, one was very dim and one was brighter but maybe not as bright as it should be. I thought I'd better have a look at the light on my Scrambler which is the same but slightly different. Well bugger me! There was only one LED still working in it but much brighter than the brightest one in the Supersport light. New number plate lights for both models are just over £30 each. I think I'll be looking to take them apart and replacing the LEDs. So you might want to check yours.
That's what my MOT tester told me when he thought the bulb on my 916 had blown. To add, it's an LED bulb as filament bulbs don't last long but the LED I have is a little shorter and so appears very dim due to not poking through quite so far.