9/84 is the date it was made: If it was fitted to an MX bike, then it woulda been an '85 model, but trail and enduro bikes are harder to know.
Width says that it was a 250 or bigger.
Colour of rim?
Late edit, after I'd read oldstuff's post: Ew, 2.50 is pretty uncommon - I'm sure they were fitted to other bikes, but I've only seen them on IT250/465/490s (in silver) and a couple of years of YZ250/490 (in gold).
They're an odd looking rim - really square shouldered.