just about the exact same bike (and story) as me. my R80/7 was basically my first real bike and first learning experience with working on one. it's been a great amount of fun, a little frustration, with excellent help from the folks here who were VERY patient with me, haha. don't be afraid to ask stupid questions.
my bike was in similar condition when i got it, with no history. i pretty much just changed all the fluids and learned how to tune it up as soon as i got it. the only major trouble i've had was some wiring and starter issues which were eventually sorted out. i also changed all the brake/throttle cables as they were pretty chewed up. the bike runs great now!
i've also got a weird "clunk" noise in the front end and haven't been able to figure it out. i was actually going to rebuild the forks this weekend to see what happens. i'd like to know if you ever figure yours out. i'll keep an eye on your thread for sure!