Crankshaft pin still challenges me

I was delighted and extremely grateful to Roy, Reg and Bernie who all had something to contribute to my enlightenment of this odd flywheel/crankshaft alignment pin.  A little flurry of phone calls and emails gave me much encouragement.  My understanding now is that it is certainly a little pin that sits in a blind hole on the shaft that locates the flywheel keyway.  Apparently other DKW motorcycles have used this arrangement.

Reg modified his shaft and had a keyway machined into the shaft.  I still have to work out my solution as I had originally intended to try and start the engine without splitting the crank case.  I tried drilling the sheered pin out the shaft, but it would appear that its hardened and the drill bit wont cut it.  So I am left pondering.

It was during these conversations that Roy pointed out to me as to why those starter ratchet sprocket (as mounted on the flywheel) might have been so heavily damaged, and so dreadfully knocked off center.  He wondered if the engine might have been seized at some stage and an enthusiastic bodger had tried to free the seizure by hammering a cold chisel (or more likely a screwdriver) onto the ratchet sprocket.
Aha! a mystery solved perhaps.
However this raised another really important question - and one that might be influential on wether I should split the crank case.
If the crankshaft had been whacked and whacked to the extent that it buggered the starter sprocket like it is...... had the crankshaft itself been bent?  Up until this point I hadn't thought about wether the crankshaft was true or not.

 I dont own a dial micrometer so I couldn't accurately measure this immediately,  but i was curious enough to get a feel for how true the crankshaft was.
I rigged up a bit of stiff wire on the engine case and bent it to shape so that it was gently touching the crankshaft.  Rotating the  crank sure enough revealed that there was indeed a slight oscillation.  But in my opinion only slight.
In order to give myself an amplified sense of the oscillation, I placed the flywheel onto the shaft and nipped it up.  Spinning the crankshaft now and measuring the movement on flywheel in relation to the engine case didnt really give me a sense of horror.

I concluded that the crank was good enough.  It was certainly good enough to continue with trying to start it without splitting the case yet........ if indeed I could solve the alignment pin without having to take the crank out and to a machine shop.

I am going away for a few weeks now for work and so this is going to be perfect thinking and decision making time.