Pretty much screwed.

[Dvsrd]

Since we are looking at an RD or R5/DS7, what about splitting the cases, so one could tap the liner from the bottom? Maybe machine a brass flange to act as a punch.
Or make some kind of a hook shaped extension to a sliding hammer, and pull on the ports? Surely better than trying to push/hit on cooling ribs

[sav0r]

That was my other thought. Split the cases and drop the crank, then you should be able to press the cylinders out from the bottom?

[m in sc]

could tap the cyls at the holes, use a long bolt and push the jugs off the studs like the triple guys do. 

[sav0r]

That would be pretty easy.

[soonerbillz]

So..
The dropping the cases is a dead end.
The piston in the stuck cylinder can't exit the case backwards.
Just too big by a bit. I guess that's why those stroked motors need the cases opened up.
So tomorrow this thing is going into the oven.. lets see what 500 degrees does for it.

[bitzz]

500 degrees is too hot.

It's not much of a parts donor. My suggestion is cut the rod, drill many many many holes through the top of the piston,turn it over and  clamp the cylinder down on something solid, and have at 'er with a hammer and chisel. The trick is to get the wrist pin broken out, the rest is easy.

[John Ritter]

Scott, do like Mark suggested, they will come loose. Put pressure on, put a rust buster in the holes, and every so often add a bit more pressure. Pulled a couple over the years like that.

[teazer]

could tap the cyls at the holes, use a long bolt and push the jugs off the studs like the triple guys do. 

He's right you know.

That is how I had to remove a monoblock GT750 cylinder that was rusted onto the studs. Take your time and after you get it to move slightly, remove the tap or bolts and hit it back down with a rubber mallet.  Rinse and repeat.  Apply more heat and penetrating oil until the kitchen and workshop stink and it comes loose.

Do it when the SO is out for a couple of days and have the fans working overtime. 

[soonerbillz]

So now I'm unscrewed.. kinda.
So I tried all the things .. except Mark's idea about tapping the stud holes.
In the end I used a torch and burned out all the bottom gasket then used a roofing scraper to dig out all of it leaving enough of a gap to stick a metal wedge in there. I pounded it in enough to allow me..
.. sorry boys..excuse me boys. 
enoughroom to puta Sawzall blade in and cut off the frozen studs.

[m in sc]

hm. what exactly were you planning on saving off this motor again??

[soonerbillz]

Unorthodox for sure but to be honest it did no damage. 
A little massaging and it will clean up good.
Gasket sealing areas are untouched for the most part.
My main desire was to salvage the case and liner.
The liner bores measure out at stock and the pistons and bores are in real nice condition.
I know this is a little cave man for you guys but it worked.

[irk_miller]

If it worked, it was the best plan.

[m in sc]

and thats all that matters. 

[Dvsrd]

If one has to resort to using wedges, maybe plastic wedges like you use when cutting down trees could work? Stihl (chainsaw brand) definitely sell those wedges as well.

And, more related to this topic, in a Norwegian FB group for vintage/ classic japanese motorcycles, there is a Suzuki GT750 owner with this exact problem. Cylinder block won't budge at all.
Any specific tips or tricks for getting a "water buffalo" cylinder block unstuck?

I was thinking, maybe the studs could be drilled out? I see that the GT has similar "pipe nuts" to the RD head nuts. So If one could turn up some drill guides that are a nice tight slip fit in the counterbore, then drill out the entire length of the rusty studs through this guide. Surely, this must be doable. But this will also present another challenge when the remaining threaded part of the studs are to be removed.

[m in sc]

http://www.medial.se/suzuki/cyl-removal/

this is the method I was referring to.