Hello!
Being the swedish MVVS importer I have taken apart some of these engines and never encountered one with a hard-to-remove cylinderliner.....
Most of the time the cylinderliner will come out if you just turn the propeller/crankshaft...the piston will then lift the liner a couple of mm...then its is easy to lift the liner with your fingers!

But one should never say never....I would warm the cylinder case with either heat-gun or if that does not do the trick...use a propane blowtorch.
Regards!
Jan K
http://hem.passagen.se/airracing