How To Unseize A Locked Engine?

Oil it and forget it. Get yourself on line and start looking for spares and shops build a folder and take a few days let the dust settle. Slowly monkey catch

 

Hey Ron, try putting a little gunpowder in the bores...............................

 

I've been watching shed and buried, all you have to do is check for a spark, put in fresh fuel and away you go!
If you're really unlucky you might have to blow out the jets, but from what you're saying and the look of the photos I'd say the jets will be just fine as they are...................

 

With your good luck i would have a go at polishing the bike as that patina might just wash off as well lol.

 

Here in Australia, it's used in the vintage car clubs to remove corrosion from old nickel plated bumpers or old bolts are soaked in warm molasses ! It was discovered to work by a farmer who had fed molasses to his sheep/cattle in a cast iron bath tub ! The bath tub was rust/corrosion free weeks later when he moved them to another paddock and washed out the bath tub !!
This really does work, cast Iron and the older steel's of the 40's through to the 60's.

 

Boil some mineral oil in an old pan and pour down plug holes. But it would be better to strip top end first.

 

Does it have to be warm?