My 1924 cut-off touring currently has one of the aftermarket aluminum crank pulleys on it. I bought a really nice stock steel pulley on T-bay a while back to add to the pile of stock parts that I plan to install back on the engine some day when the engine has to come out for work.
Looking at the stock pulley, I see that there are two holes on the inside and two on the outside. One of the outside holes is smaller than the other three holes. The crank pin fits through the three larger holes, and then is retained inside the pulley by a cotter pin. The smaller outer hole is too small for the pin to fit through.
A question drifted into my head, what is the smaller, outer hole for? Is it just an artifact of the machining process?
I use it to push the crank pin out with a drift.
Thanks Kenny, I should have looked at the service manual first. It shows a picture of a drift being used exactly in the manner you described.