AirCooledSuzuki

What is the best way to remove the paint from cylinder barrels without damaging the bores?

Vapour blast, beadblast, (won't take metal away). Mask up and good post-blast clean up.
Baking soda, safer, easier clean up, but messy in use.
Notromors, if you can get a tin of the old stuff. New stuff is shit!
If the paint is flaky, give it a good wire brushing, get rid of all the loose stuf, and Hammerite it gloss black.