Since I was one of the people who started reading the Harry Potter 7-book series just as the new movie based on book 5 came out, I had no idea what I was getting myself into. It turns out that Harry first appears riding on a flying motorcycle in the first book, Harry Potter and the Sorcerer's Stone. Then in the last book (book 7) just released, Harry Potter and the Deathly Hallows, he again rides on the same flying motorcycle, this time with an attached sidecar.
The rider of the bike is the character Hagrid, a giant of a man. The owner of the bike is Sirius Black. You'll be following these two main characters throughout the books.
J. K. Rowling's astounding work of fiction took me the better part of six weeks to get all the way through to the end of book 7. You say this is a children's book? Maybe book 1 with 319 pages is but from then on, it gets darker and darker as Harry ages from 11 to 17. Book 7 is 759 pages of pretty much non-stop battle scenes. The new movie, Harry Potter and the Order of the Phoenix, is based on book 5 that has 870 pages.
I was startled to see a motorcycle in book 1. When I got to book 7, the motorcycle was there again, this time outfitted for battle.
Harry Potter was a very good read and even better since it had a magic motorcycle in it. Way to go Ms. Rowling.