It's highly recommended to test, inspect, and maintain a "New to you" machine. Everyone just wants to ride , wether you're 14 or 40, or even older ( like me).
Think about the fact that it's 20 yrs old. Rode hard, put away wet. It's going to need some love and attention. Could be as simple as a sticking throttle cable , TORS box, or slide. Or it could be worse.