First step is to take the clocks off and take the case off (I don't know why some of these pictures are upside down)...
Then separate the two boards...
Then lever flat the little black tabs to remove the led box and remove the box. Be really careful with this, don't drop it or be tempted to take the plastic bit out to see what's in there, it'll stop working if you do. Place it face down on something soft out of the way.
The little white squares on the board are the surface mount leds. The ring around the outside and the two at the top illuminate the rev counter and the six in the middle the speedo...
You have to heat the solder on the pads under the leds from the ends of the led and prise the square away with either tweezers or small pliers. This shows the first one removed. Use a solder remover suction thing or braid to remove the solder from the pads or soldering the new leds in place will be much more difficult.
Place the led in place in the right orientation (you get instructions) and heat the pads sticking out from the led and apply solder. If you apply too much heat the led will melt and won't work. Here's the first one done and you can see how much brighter they are.
Here's all the rev counter ones done. I didn't bother doing the speedo ones as I stick tape over it anyway. The orange led at the top of the board is the shift light.
I then replaced the shift light led with a bright one the guy sent me when I asked his advice on making this brighter...
This is the rebuilt clocks with the brighter outside ring and the dimmer speedo. You'd replace them all for a road bike.
This shows the brighter shift led...
If you're going to do this job buy the kit from the ebay link I posted above. The advice I got and the instructions were superb.