SUSPENSION LINKAGES
A fairly common issue on used bikes, the Japanese manufacturers tend to be a bit stingy on the grease during assembly, and that means linkages seize up on older bikes. Ask when they were last stripped and look for any signs of rust (bad) or grease (good) that hints to their condition. They can be rebuilt, but if they are badly corroded sometimes it is cheaper to buy a better condition used set of linkages.