My '87 Elite had lots of little problems like that when I first got it. On an older bike, you will have to "catch up" all the maintenence that has been neglected over the years, including replacing old rubber (tires, belt, etc.), fluids, etc. Cables get rusty on older bikes...
I bought my '84 QT50 from a motorcycle mechanic who had fixed it up for his son, so it was already in good shape when I got it.
david.