I picked up an 87, with 1200 miles on it, about a year ago. Mine ran, but not as good as yours sounds like it does. I got a service manual, and did a valve adjustment, spark plug, oil change, and replaced all filters. Since then, the only thing I´ve done is change the oil every 500 miles. I´m now at 3500 miles and it´s still running great. According to the service manual there are lots of things to inspect from time to time - I would recommend the manual.