my advice. If you're not sure what it's worth, and you're not sure what you're going to do with it, do you really need it?
How much is your time worth? What will it cost to do what you need to to flip it (including time, gas, and tools)? Sure, you might make a couple grand, but if it takes you 200 hours, is it worth it for 10/hr? Then factor in the "what-ifs." What if it needs more than an engine? What if you get stuck halfway through the swap and lose motivation, time, know-how, or money?
If the pros far outweigh the cons, go for it.
Or... think about all the time you could be out riding your dirt bike or camping with your kids if you
didn't buy it.