I think the procrastination doesn't necessarily result from lack of motivation. If it indeed results from lack of motivation, then there must be some tricky difficulty hindering the swift achievement, such as some unanticipated factor which can't be controlled by myself or overburden. Otherwise, if you are well-motivated, why don't you progress swiftly? Besides the tricky difficulty, I think my procrastination mostly results from reluctance or lack of energy.
I usually do the things I like first and procrastinate those I dislike to the later. In elementary school I always finished my homework first after school before doing something else. In (junior) high school I always studied science prior to society for exams because I like the former more. But since undergraduate time, most of the subjects are what I like because it's me who chose the major. If I delay to study the subjects I like, it's usually because I can't understand some material, otherwise I would progress very fast unless there are other things taking my time. As for dining, if there are friends inviting me to eat together, I would go with them without procrastination; if there is no partner to eat together and I need to go to eat alone, I usually procrastinate until being very hungry. The same is true for travel. If there is no friend to travel together, I often even don't bother to plan to travel, not to mention to procrastination. Aside from these scenarios, I may procrastinate the things I like to do when I have a bad mood or lack of energy, such as due to not sleeping well the previous night. And for the things I am extremely disinclined to do but must do, I usually procrastinate to the final minute to do with annoyance.