Step one is get a shop manual. Your problem could be its a 92, and how good of shape is the motor actually in? Crank seals, top and lower end, the cooling system, can all cause spooge, thats the black goo. It would be nice if its just a jetting or plug heat range, maybe even a clogged silencer, but, you or a qualified mechanic will actually need to find out. Most manuals, you can start at the front with some basics tools and go through the bike. Later you will find out, the daily/weekly/monthly/yearly maintenance chores that prevent things like this from happening. It will help you make more precise guesses as to the issue, which IS in your garage, not mine, unfortunately. It would make things easier?