Complete Vespa smallframe engine strip down and rebuild.
6. Removing the crank.

To get the crank out of a smallframe - as you'll need to to change the clutch side oil seal - you need to undo the nut that holds on the primary drive gear. This is held in place with a tab washer that will (well should) have been bent up to prevent the nut from turning inadvertantly. Flatten the washer and use a penny jammed between the primary drive and the clutch basket gear to prevent the crank turning while you undo the nut.

There is a woodruff key here too so make sure you keep this safe. Now remove the gear and begin to knock the crank free. Place a piece of wood on end of the crankshaft where you have just removed the primary gear and knock the wood with a hammer to gently push the crank out.

With the crank out inspect the crank and the rotary pad for any damage.