I used the spring from the choke assembly, wrapped around the outer shaft arm and hooked to the inner one. bent in the inside link's "tang" that's in between 7 and 8 o clock in the pic, so when the primary opens about 2/3 of the way, the arm hits the secondary shaft link, and the spring takes the shaft with it to open. you can't damage it because the added spring lets it stop when it needs to and won't force it past it's physical limits, closing when you let off. a thin metal piece from a different part of the carb removed from the strip down process, was drilled out in one spot and a paper gasket made, and blocks off the vacuum secondaries pot. stock parts reused.