If it is real nice I would say 1500-1800, it is hard to judge though as it depends who wants it and how badly. Someone waiting for a mint one for 3 years might be willing to spend a bit more.
Pics would be great. Even if it has sat covered all this time it will take some $ to get it running right and these are not super collectible bikes as far as I know.
For me Ebay is always the best way to determine a bikes value - do some research there or just list and see what happens.
Lots of old Hondas, 2 Yamahas, 2 Kawi's.