An Indian Enfield.
I have two of them. There's a very active group of enthusiasts who can help you with advice, instructions, parts sources...
Try this site.
Or this one.
And by all means sign up for this yahoo group
. It's for Interceptor owners, but we all seem to own an Interceptor as well as other models, including quite a few Indian Enfields.
Here's a photo of mine, as it was from 1984 until this year when I tore it down to rebuild in more original form. (the fenders and engine are from a different model)