If the sprockets get sharp-pointed teeth, they have to be replaced. Further use will actually undercut the points until they fall off, leaving stub teeth. At that point the chain will slip. However sometimes the tip of the teeth gets deformed in other ways, especially if you fit a new sprocket with a stretched chain. The small sprocket in your last picture looks as if this may have happened to it.
Deejay is the man with information on where to buy Scott Bonnar parts. He may be away visiting his parents in Brisbane at present, so he may not get back to you right away. If all else fails, send him a PM.
