noob with questions

i got this awsome deal on a dirtbike. my uncle straight up gave me this old school bike... the only problem is that it needs quite a bit of work, and i dont even know the year or model... all i know is its a yamaha, and i got a number off the frame below the handle bars... the number is dt1f-110 480... if anyone can help me identify this thing, then i can get it goin and start riding. i called a couple places and asked about it, and all they could tell me it that it is really old cuz they have been using 17 digit vin numbers for like the past 30 years or so.

thanks
-matt