Whoa, I was cleaning up and found an identical express spring.
I have no idea where it came from cuz this is the only express I've ever seen around here. ?! The dang thing was hanging from the peg board, on a hook.
Anyhoo, I spun the 2 springs together then drilled and tapped an M10 into the end. The starter lever hole has a 1/4 npt threaded plug to cap that off. There's a case vent on the back side. Doi :)
NoW, I'll close it uP.