There are TWO of those tiny rubber valves in each pump. You probably have only one of them displaced. IF both come out, the pump won't put enough fuel to the carbs to keep the bike running. With just one out of place, it seems to be able to keep up, but clicks a whole lot of the time the bike is running.
Easy to disassemble, and fairly easy to push the little rubber diddy back into it's holding place.
I think mine has been doing it again this past week, and I forget to take it apart after I get it home from work in the evening. I may have a go at it again this weekend.