Well, this is kind of interesting as the ’41- ’42 TD-15 and ’46 – ’49 TD-20 motors along with the TN 25 and 26 motors all used two separate keys. One to align the flywheel and one to drive the round magnet. These magnetos also used the plunger points which had a pushrod riding on the flat area of the crank to open them. Later TN 27 and 28’s used the new universal magneto and had only one key which aligned the flywheel and drove the points cam.
This definitely looks like the earlier style crank but the single keyway and double flats are puzzling. With two opposite flats, each spark plug would fire twice for each revolution and it wouldn’t matter which way the plugs wires were hooked up. I wonder if it isn’t a left over ’51 or early ’52 crank with the old flats machined in it?
