Not sure if this is allowed, but what’s a good value for a well maintained 07 GS500F?

Fairings in good shape, normal wear and tear for an 18 year old bike. Carb rebuilt, changed sparks and oil, new battery, new tires, etc. All within the last 3k miles. I checked and adjusted the valves about 1k ago. Chain has been inspected and adjusted too.

21,000 on the clock.

I fucking love the thing but I really want to upgrade to a GSXR 750.

Not really sure what I should charge for it if I was to sell it or how much I could realistically get.