In my experience, it only depends in the way that these words are being used. Motive: Is probably either "good" or "bad" reason for doing something. "He has bad motives" - can mean that he does something for a bad or selfish reason. Good motives are usually not selfish. Motivation: Usually means the desire to accomplish something. "He has a lot of motivation" or "He has no motivation, so his work is very bad"