Hi there!

Wondering if anyone of you guys know how to extract this stem adapter I have in my bike:







I've already taken out this screw and bolt from the upper part:





I believe it's a threadless adapter, isn't it?
I've tried with WD-40 and a bit of a hammer, but don't wanna do too much of it until somebody tells me I'm doing the right thing.

Anyone?

Thanks a lot!