Not long ago, guys were figuring out complicated ways to get led lights working in their gauges and pilot boxes. The hardest part was adapting a bulb to fit the wiring harness.
This is no longer difficult. Now you can just buy a replacement light bulb that fits right in the socket. The bulb is called a BA9s. They come in different colors. You can get white, red, blue, green etc. White works great for the speedo and tach. White also works for the bulbs in the pilot box, but you can get red for the oil light, blue for the high beam and green for the neutral light if you want.
LED's use less power than regular bulbs and are sometimes (not always) brighter. I would say that's the main thing, the bulbs are usually bright enough but once in awhile they are not as bright as one might expect.
Replacement bulbs for tail lights are easy too. Just get an 1157. It should pop right in and work. Being that this is a light that other drivers see, it's important to get a very bright one. I like 1157's that have at least 45 LED's on them. The more, the better. Of course the more LED's the more expensive the light is.
An easy source for finding LED's is E-bay. There have been a few bulbs I bought from E-bay vendors that were not very bright and one of them failed within days. And once I bought an 1157 LED that would not fit into the socket. I think it might work for a car's tail light but the shape of the base would not fit into the socket on any of my motorcycles.
One thing I have not tackled is putting LED's in turn signals. Reading the SOHC forums, many have had problems with getting the turn signals to blink because of the light load. Regular flashers won't work because the LED's don't work correctly with the relays in the flashers. So people installing the LED turn signal lights have to change the relays too or figure out other things to do. And then there's the brightness factor too.
I'll wait on LED lights for my turn signals until it gets a bit easier to do.
