This is due to the shape of the 10mm led replacement lights, they are projected dome tops, you will need to shave the top flat in order to get it to shine correctly to light up both the speedo and the fuel guage. Sand with some 240 grit till its flat then 400 to smooth, then 1000 wet sand to smooth further, then get some polish I use mothers aluminum polish to get it perfectly clear again. Optimally you would want a concave face but its hard to get something to drill that shape and then harder to get it sanded smooth with it like that.
But if you really wanna try you can put the bulb lightly in a vice then with a drill bit roughtly the size of the bulb (10mm) drill the center of the bulb out, this is hard because the dome will make the drill want to slip, a drill press is really the best. Dont let the bulb get too hot from drilling and dont drill too deep just to the top of the curve. Then when you get that done you should have a pretty smooth top from the drill bit, you can put some polish in the hole then a piece of cloth then use the drill lightly pressing to spin the cloth, dont go too fast or you will generate heat. Check it every once in a while to see if its clear and when clear its done, stick it in.
