80 revolutions per minute is about the right speed for a Wurlitzer band
organ crankshaft.
 
The pump sticks shouldn't knock, if everything is in alignment and any
excess play between the pump sticks and the metal to which they are
clamped is removed.  This may require sawing a little more wood from the
saw-kerf that allows the pump sticks to be attached to the axles of the
pumps and crankshaft, and clamping the sticks tighter.