Hello how are you today?
I am doing well. I am interested in your bike you have for sale. I was wondering about the condition, is it road worthy? 
Hi yes absolutely its road worthy. Maybe the tires might need to be changed in the long run, but otherwise its as great as new
In looking at comps, this bike i valued at far less. Because it needs new tires and there is no mention of upgrades, would you take 600? 
$600 is too too less for what you're getting. I can probably give it to you for $800
Could we split difference and go $700? I can come pick up. 
This is a model of the year 1987 and we know old is always gold. I can sell it for $800 nothing less than that sorry. 
I will $800, if you are willing to meet me in a central location that works for both of us.