This is like another thread using a puller, but it does not rely on using the puller (or pullers as some have conjectured) on your jugs' cooling fins.
Where one thread said use the fins to hook the puller, another approach is to run a tap down the bolt holes (assuming you can or have removed studs) and attaching the puller with bolts in the holes you have tapped out. Suck or blow out the filings , of course, and screw down the puller with the clean threaded stud channel. No chance of breaking cooling fins this way.
It took a while, heat and months of tightening and letting it sit along with concotions of ATF, acetone, and Aerocroil. The night it finally started comming loose a friend was tapping on the puller while I twister the puller. I used a round aluminum slug between the puller and piston as if the piston was not unsaveable junk. Oh yeah, heating things up can't hurt. This was a tough one, the penetrating fluids puked out the exhaust port because the piston was at the bottom of the stroke; unlike the 4 strokes where it just accumuates and pools on the piston and goes seeping in where you need it.
If it didn't work I woudn't post it here.
This was a stubborn one. Patience is the key, torque it and leave it. Come back in a week and try it again. Tap on the puller and twist. If it isn;t working leave it for a while. This does work.