I spent half a working life mitigating the “ten-thick-stubby-thumbs-on-each-hand” activities of university academics, Ph.D. and other student pond life so forgive me for cringing at the thought of letting anyone I didn’t know loose with any sort of hammer!
As usual I find myself in agreement with Mr. Moss’s words of wisdom save for the lump hammer bit. I also feel uneasy about removing even small segments of crankcase to make the removal of the crankpin screws possible. It will certainly work but I have to question the idea of chopping bits off fundamental castings unless there is no other way. On balance I think I’d rather attack the screws.
I note that Robert said he has access to liquid nitrogen and further that he has already made fittings for a hydraulic push which should provide a lot more controllable pressure and rather more kindly too. After all the pistons might be recoverable, something that will only be known when they are out. The one merit a hammer has is that it provides a shock load that does sometimes work when all else has failed.
On the positive side I agree with everything else, a good long soak can do nothing but help. Also the suggestion of making a soft bush is an excellent one and the suggested working sequence is the one to follow.
“First do no harm” should be pinned over the door of every biker’s workshop! Always try to work on the basis of doing nothing irreversible.