Agree with Dave, and here's my take...
In good running condition with a CLEAN Title, its worth max $1800. There are too many newer and more appealing bikes in the $2000 range.
Starting at $1800, I'm going to make some "worth" deductions.
I'm guessing the tires are 12+ years old since it's been sitting around

-$400).
Unknown Engine Knock: (-$500) that's a low deduction.
Lost, Missing, or Skip-Title: (-$500)
I'm in the $900 range IF you have clean title in your name. I'm in the $400 range without a clean title.
The last 3 fixer uppers I've bought were all in the $600-$800 range. They needed some TLC but none had knocking engines.