Nope I dont think thats it either. I think it is this one in this schematic of Garelli H2
If you look close the shaft looks almost the same as the Garelli H1 except that the H2 shaft has the keyway (#17) slot to hold the one way roller hub.
Here is the Garelli H1 schematic. See, no keyway.
Yes this guy needs to pull the part then start asking.