Hi Michael
I do not own a R yet, still looking for one, but I do have 3 1983 CB1100Fs which are all running which I have collected and re built the Engines in each one, and these Engines are the same as the R with the exception of all the special performance parts in the R
As Andy stated removing the Cylinder is a major job, one of my engines that had never been apart to the best part of 2 days to remove
If you have a hole in the crankcases the most likely culprit would be a broken con-rod, which would have also damaged the cylinder liner, piston and maybe the valves/Cylinder Head
Finding replacement Crankcases could be a problem, conrods are easy to find, and if the crank is damaged 900 ones can be used, and a cylinder liner can be replaced
I live Crawley, if you would like me to have a look PM me your phone number
Regards Keith