That was my 2nd thought. I'm sure you could source some coloured plastic, or just paint some clear stuff you preferred shade?
You must have too much time on your hands! Although, I can talk, just took a photo of mine int he dark! I will be fiddling with my bike when it can go in a shed. Dark too quick and getting too cold for much fun out in the evenings isn't it?! :roll
They are normal white bulbs with rubbery green covers(sheathed with a coloured " condom" as areessmill put it :wink), They are pretty easy to get at once you have the clocks out. It was one of the first things I did with mine cos only 2 bulbs were working:roll