Originally Posted by
fietsbob
I suspect it's the stuck seatpost effect, in the corrosion and rust of the steel and aluminum bonding them together* .
Though it's an aluminum quill stem, and steel steerer fork, look up stuck seat post threads from the past.
*Galvanic Corrosion
Unfortunately, this seems to be the case.
There is no sign of a stem bolt or wedge, but the stem is locked in regardless.
Should I just try to use more and more leverage on twisting the stem till it releases (or breaks)?
I live on a tropical island, which is very unhealthy for bicycles. Warm, salty, humid air corrodes everything.