Real-world motorcycle value

Hey guys:

I have a friend who is considering selling his motorcycle. He's 63 and no longer confident of his ability to handle it.

I'm not a motorcycle guy, so I'm going on what he told me:

1998 V-Star 1100. He didn't recall how many miles. I know he didn't ride at all last summer and now it needs a new battery, which he will do. I've seen the bike in the past and it looked very presentable.

What would be an "in general" range to ask for something like this assuming it is completely roadworthy and looks good?