Sounds like the bevel at the top of case in not there!

When no bevel, the flange on the top of the sleeve/liner makes the aluminum pinch the sleeve when the heald bolts are tightened. ( did this make sense? in a hurry)

Try heating it up with a torch (propane) from outside so case grows first then put plastic prop or similar into exhaust port and by turning crank with wrench or prop let piston push sleeve up far as possible.
Now you still have to figure out how to grab top of sleeve or pry with out messing anything up.

This will work IF THE PISTON CAN BE REMOVED FIRST
 machine an aluminum disk with a step. the smaller OD fits into sleeve and the larger OD some smaller than Sleeve OD. Needs a hole for bolt to go through.

a piece of tubing that will be larger in ID than top of sleeve od(flange) and a heavy washer or another machined piece.

Threaded rod through it all with nuts to extract sleeve.

Machined piece goes into bottom of sleeve
Tubing goes on top of case with washer on top of tube.
Bolt through the 'stack'

What Dave said.

And an aluminum pry tool may do damage. What ever you do super careful is key.

The case can be heated some past boiling point of water/ spit.
Can go up to 350F or so.
Makes sure you keep the flame moving over surface and not to close with the point of blue flame, 1-2 inches.

If oil and gunk is holding it in it will boil out case/sleeve joint and will usually then slide out before cooling.

If you can push from inside(like Dave said) or use plastic in exhaust and turn crank it should come on out.

Some times a thumb or finger with glove! can be inserted and crooked to pull out sleeve.


UNLESS
the top of the case bore has been deformed and pinched into sleeve.
Some times after cooling down you can grab top of sleeve with hand and kinda twist and pull and make it 'Screw' out, this usually marks up sleeve but this is no biggie unless really bad. polish it to remove high spots of marks(grooves)
If the top of the case has deformed tight on sleeve cut a bevel (45deg is good) 1/16-3/32inch wide/deep in top of case bore BEFORE attempting to reinsert sleeve. or your stuck again.
If there is no bevel at top and this is not what had sleeve stuck cut the bevel anyway or next time.........

The bevel can be made with file, dremel, auto valve seat stone by hand or lathe.

If you go through the trouble of centering it in a lathe you can help top end fit even more by enlarging(relief) the top of the bore by about .005+(.010+ total) to just past the depth/end of head bolts in case

REASON: when head bolts are tightened the stress in the threads causes case bore to bulge in the thread area.
This bulge is reflected into sleeve and is of no help to seal and life.

Some engines have bevel and bore relief and some do not.
Even same brand and same size may or may not have one or both.
Don't ask me why.