You can never know at what price a dealer can sell at. The reason is because you won't know how the dealer came by the bike. I know because i used to have a business selling cars and bikes etc. All be it in uk but the same applies universally. Your best way of going about it is to not be cocky with the salesperson but do the opposite. My advice would be to go and look at the bike and be like oh, i love this bike but i can't afford it. Build a rapour with the salesperson. Walk away, return, tell them again how much you love it, be nice, fondle the bike, be prepared to walk away again. Sooner or later they will ask, how much can you afford. Tell them your lowest and say i just have 5k for example... if you've built rapour the seller will let you know somewhere near his minimum at that point. If his minimum is high and you believe him it will be because of how much they have invested in the bike. But coming across as mr know it all is a huge turn off for sellers. All sellers love customers who love the product and feel empathy if they cant afford it.
Do you not have secondhand bike auctions in usa? That's where the dealers buy from if it isn't a part ex anyway. Save yourself the commission by taking the risk at an auction and spend the saved money on doing anything it needs. In uk anyone can simply register and buy at auction. You have to have cash. Also, sell the bike private because otherwise you lose on the part ex and pay commission on the new purchase. Reduce it by selling private. When i was at college i would buy cars at auction and sell them private. I always had a cool car, loads of cash and didn't have to work, just study.
If the economy is bad, we sometimes would sell at what we'd bought at just to get cash released. The economy directly affects vehicle market. Try to find out how long they've had the bike. You have to weigh everything up, but you'll never know how much they have invested in the bike so... find a sympathetic salesperson and build rapour. Look at other bikes, not just one. Look at cheaper bikes infront of them. If the salesperson is a real cock, they'll force the bike with the most profit in it. Also pay attention to how interested the seller is, if he's walking away from you, not as a game but seriously not interested, then the bike doesnt have much profit in it. Am i teaching you abc now. Sorry. I will now shut up lol. Oh, and bikes at the front are ones that are new or have the most profit in. Bikes at the back have lower profit in.