This is one of the far-fetched ideas, but I'm asking you to examine different cognitive function's connections to motivation. Everything else probably relates to motivation more than any of the functions. Nevertheless, I'm interested about this. I'll give my 2 cents about this.
Se: Seeing everything in action, seeing that something happens and that you can do it. Exercising this would give motivation for short-term projects that have quick feedback.
Si: Studying past data provides conclusive evidence that it's worthwhile to go to study, go to work and buckle your seatbelt. This would provide motivation if you were to convince yourself that replicating some earlier circumstances would also replicate the resulting success.
Ne: The world is a miracle and all that. You can do anything, yes?
Ni: The past gives me the ability to see the future, so I should be pretty motivated, ehh, perhaps or maybe not. If I care. It's all so long term.
Ti: Well, there are descriptions of things and procedures, and it really goes on at many levels and it has to do with perception, interpretation and all, but it doesn't really push me to do anything.
Te: I'll have to do this because it is of utmost importance! If I don't do it, this and this will happen. Also, these good results are a direct consequence of what I do or what I don't do.
Fi: I've wanted to do this for long time. I just feel it in my guts I have to do it. I feel fulfilled if I do this - it's important.
Fe: The public opinion holds this goal as worthwhile. I can use the public opinion to my advantage if I do it as well. Also, I feel pressured and obliged to do this.
So, what's your take? What functions are more closely tied to motivation and how?