Whilst you have the binnacle out I'd change the 2 bulbs for illumination of the dials. They are in the twist fit holders at the top and shoot light up the white channels
I've pulled the cluster (used a lemon zester courtesy of Mrs B's cooking utensils) but there doesn't seem much slack in the cables behind so I can't release it from the dash to get at the bits.
I've had a poke round the footwell and can't find the speedo cable clip referred to in the earlier link to introduce a bit of slack into proceedings.. Am I being a bit thick..
Will dig out the haynes and have a look see on the ruski site.. don't want to yank things out and break the speedo/fuel gauge..
Sorted - managed to reach behind and disconnect the speedo (bit better access than my old Vespa ) swapped the dimmer pot over and put it back together again - it even works!
Old pot has broken solder joint identical to the others on this thread - if anyone wants a free one to solder let me know. The new bit was £22 from MB.