Above: All emblems from chapter 4
Emblem 1: You must be Sherry to get this emblem. Once Jake stops the bike and you’re supposed to shoot the fuel truck underneath the chopper, first aim to the left. There’s an emblem resting atop a sign sticking out of the side of the building.
Emblem 2: After the chopper is destroyed, Jake and Sherry will make their way down several quiet alleys. Keep your eyes left as you cross the street to find this emblem on the hood of a car - one which still has its headlights on.
Emblem 3: At a certain point, Jake will leap from a window and fall through some canopies back down to street level. From the point where you hit the ground, simply look to your left to find an emblem.
Emblem 4: Soon after the previous emblem, Sherry will have to take the high road to unbar a door for Jake. After passing through this door, you’ll come upon a ladder. Before climbing, look beyond it and to the right.