81 R65 value. Some guidance please.

[brianjonesphoto]

A buddy of mine will soon be selling his 81 R65 am I'm trying to help him figure out what it might be worth. I don't know much about the bike but here's what I do know. 9000 miles on the clock, Dual disc (that have just been rebuilt) I believe it has some sort of fairing on it. It's all original ready to ride. In good condition, but not mint.

I've got no idea what the market for airheads is like what's a fair starting price for this bike? $2500? $3000? More? Less?

Thanks.