The two main pop bumpers on my Mata Hari aren't very sensitive and aren't very strong when they do activate. Last weekend I cleaned and tightened up the switch gap but it didn't make much of a difference. When I was doing that I noticed the "stem" that goes into the pop bumper spoon has wore a hole in one of the spoons so obviously that will need to be replaced. I've never disassembled or done much work to pop bumpers other than switch adjustments. What parts are typically needed when someone is wanting to "revive" their pop bumpers?
I found a good image of the individual pop bumper components and have attached it.