It depends on how much of a mechanic you are. Carb rebuilds aren't incredibly difficult, but there's a lot of small parts. I'd also take note of the car parked right next to the bike. Parked that close, they probably belong to the same person. Stereotyping a bit, they might be a kid whole likes to go fast. Makes me wonder how the bike was treated, and if there are any problems that haven't been disclosed. Just coming into riding season, and with the current fuel prices, most people would probably want to hang on to a decent bike. If you're comfortable with taking a chance on the unknown, go for it. All those old UJM standards were pretty good bikes.