Motorcycle Repair: Sportster, bearings, amount of time

Question
Hello, quick question for you, I was thinking about buying an old sportster from a friend but it has been sitting in his garage for about 20 years.  My question is this: how much damage can be done to a motorcycle by letting it sit that long without starting it?  What likely needs to be worked on to have it run properly assuming it ran well when it was parked (other than a battery).  Thank you!
Andy

Answer
You will probably have to rebuild the motor. Over that amount of time the bearings will rust and seize up. You will also probably have a rust ring in the cylinder from the rings sitting in one place. the carb will be gummed up as well
Good luck and happy riding
Mike