That's a terrible quality pdf. For $14.99 you can purchase the enhanced version here: http://www.basicfeynman.com/enhanced.html It was very cool of the publishers to allow this, and they deserve our support.

Otherwise, if you must download the basic version, go to the piratebay and search for "Feynman Lectures on Physics (epub,mobi,html) - FIXED"

Please note that this is only a small subset of his lectures. They are the "Six Easy Pieces".

  SIX EASY PIECES, taken from these famous Lectures on 
  Physics, includes the most approachable material from the 
  series

The pdf is a fairly accurate copy of the print books which I own but which are heavy things to lug about.