So I've realized last night that the link is actually a makeshift valve with the hose in a groove molded into the plastic shell. As Driver mentioned, it looks like the crankcase pushes air through the hose at the bottom of the tank. Oil is then, forced out of the hose at the top, (assuming the hose feeds to the very bottom of the tank) and into the bar.
The linkage itself sits inside of a spring with a cap in it and the hose goes between the link and the shell between the hose guide grooves. I should be able to put the rest back by the end of the weekend. (Its a back burner project due to a busy schedule.)