I replied to your other post. From the CL post and pics, I'd offer $800, but pull the cash out of your pocket before you say anything. Looks to be in good condition and you are in the Seller's season. He'll get $1200 easy enough. Had this been Fall, $800 would be pushing it in my opinion.
Seller prices high and hope to get a little lower....unless they see you coming then they get more than they were expecting.
For that bike, make sure all the covers are there, no left side pic. The back seat is intact and you have the backrest. As long as it starts quick and no smoke out the back.... I'd go to $1000 but that's what he wants, hence the listing of $1500. Anything over $1K is just more than he was hoping for.