This was asked on the K1600 Forum So I wanted to Cross Post my answer here so it might help someone else.
Originally Posted by B
On the top box on a GTL anyone have pictures of how to remove the bottom liner, or a write up, or even pictures? The search feature will not take short words like top and box only “Topbox” which I could not get an answer from.
It is not hard but there are a lot of screws to remove.
1) remove all screws in the inside of the lid. This will remove the back rest & the top half (color part) of the lid. Also the brake light & inner courtesy light. The back pad has 2 screws outside by the hinges. they are about an inch inside the bottom edge of the back rest.
2) unplug the wires & move all wires to the front (hinge side) of the topcase
3) remove the pins that hold the top of the prop shocks. A small screwdriver is needed to release the spring clamp on top of shock.
4) remove the 4 screws that hold the top to the 2 hinges & remove top.
5) remove the screws in the bottom . 2 on top lip by each hinge 4 more on the lip , 2 on the sides by the shocks & 11 in the bottom. DO NOT
remove the 4 screws at the back by the handle. these have what looks like rubber washers around them. These hold the lock in place.
6) remove the allen bolt that holds the "Release Knob" & remove knob.
7) pull the rear outer shell away from the inner shell at the handle & lift the inner shell. Make sure the "orange" tab at the release knob is pushed in so it clears the liner. Orange tab on the outside below handle will be out.
8) unplug the "Central locking" wire from the outer shell to the lock (inner shell)
9) Slowly lift liner out from the rear.
10) The locking part that holds the case to the bike is just sitting in place so DO NOT
tip lower outer shell over or it will fall out. I used duct tape to keep mine in place while working on the shell.