Somehow between moving the windshield to another layer at 3:40 and adding the subsurf modifier at 3:50, you added faces that engulf the handlebars. How did you do this? It matters because later on at 7:00 you run a loop cut that goes around the entire top perimeter of the body... if you added the faces right. The way I added them the loop cut goes around the gas tank support, missing the front of the body.
Hmm interesting, it looks like he skipped that part, but 4:12 gives you a good view of that area and it looks like it's just extruded inwards to meet at the middle, with a triangle to fill in the gap in the bottom right.
If you get stuck, feel free to post screenshots in the Community and we'll give you a hand.