The GSX1100S Fuel Cap Key

So the other day, Ninpoco’s bike had gas dripping from the cap,
and when I took it apart, I found it had a spring-plate-like mechanism pressing the rubber gasket in place.
The rubber’s tension had weakened, so it would leak when the tank was full,
so I cut a paper gasket, tightened it down, and that fixed it.
But the owner said they didn’t like that! Since only the cap was available, we went with a combination approach.
 

 
There’s no reason it can’t be taken apart ★ ↑ The protruding plate is the stopper.
There’s a spring inside that gets pushed out when activated. Since it doesn’t pop out, it’s safe.
 

 
It’s designed to catch in that groove
 

 
I see, pretty clever
A note to remember ★