Thought I would give this another try with photos. When disassembling my 85 K100's fuel cap assembly the centre  portion of the plastic nose cone and housing popped out (see photo 2). What I am trying to determine is how the nose cone is secured in the outer housing. I can only assume that it is press fit into the outer house (photo 1) to prevent it from sliding out freely as there are no fasteners or components that hold it in place. I have  already installed the gasket kit (16119062461) and this is the last hurdle to getting my bike ready to ride short of having to try to track down another gas cap assembly. Any comments or suggestions would be greatly appreciated.

Thanks,

elementalfire

Haven't had my hands on an 85 gas cap lately but on the later ones the way to get the "sprung cup" (as I call it) in place is:

Remove the lock core from the gas cap. (You'll see why later.)

Put the cup on its spring and turn it 1/4 turn counterclockwise until it drops into place and hold it in place with downward pressure. Keeping downward pressure on the cup, partially close the gas cap and then put a pen/screwdriver through the lock core hole and keep the cup pushed down with that as you put the assembly flush with the bottom of the gas cap and then put in the three machine screws.

Then reinstall the lock core and be sure to test to make things are working properly before you test close the gas cap.

Why not drill the SidecarPaul hole in the top of the cover at this time. You can blank it with a small grub screw and neoprene washer.

If you ever have a fail you can access the mechanism through the small hole with a small flatblade screwdriver to open the cap. Good security too if for some reason it won't open after maintenance.