Are there diagrams anywhere? And my bike is totally stock - black windscreen. What is the bulb that lights the license plate? i just want to swap it with an LED, and need to know what the base is.

 

Anytime you have a bulb you're unsure of, remove it, and take it to the autostore, even Radioshack or a truck stop (cheapest). All of these bulbs are standardized and sometimes you can swap bulbs for others. The packaging (at the store)will specify the bulb part number. On brass based bulbs, the number will typically be stamped on the base. On the other ones (all glass) sometimes it's printed very small somewhere on it.
Drive semis long enough and you'll know more about bulbs than you ever wanted to, lol.

 

or read your manual that came with the bike..

 

I just took my cover off for the bulb. I use to work in a parts store so simply take that bulb in and get a replacement. You will find it no problem.