[denisond3]

Assuming you have that crank sprocket on the right way - it can be put on backwards I think - then I would think it is either a burr on the crank surface or on the inside of the pulley, or that the woodruff key isnt seated properly. I recall it has to be really 'flat' down into the groove so as not to interfere with the groove in the sprocket sliding over it. You might need to take a file and remove any burrs or gouges on the sides of the woodruff key.

I call the crank 'pulley' a sprocket, since it has 'teeth' on it.