I'm kitbashing Cyb deluxe Unicron, but I need some tips on removing his head which is attached to a bolt like-device (I have no idea what the term is for that) on the vehicle mode's radar-dish thing.

I have the same problem. Let me know if you ever find a solution, I'll do the same if I get one first.

Good luck with your project.

Thanks, I'm half tempeted to just cut it off.

Its just a rivet. You just need to be careful that you don't break the connecting pin from the dish to the tank body.
That is a pretty thin piece of plastic. You want to take a small screw driver(or pin previously removed from another tf) and hammer. Then tap out the pin that connects the dish to the tank body. Once you do that separating head and dish is pretty easy. All you need to do is take a thin flat head screw driver or knife and work around the edges of it. The head should pop off with little effort.
I did it for a Bludgeon custom I made a few years back

Thanks alot Rat.

you'll be better off heating up the rivet from the bottom, getting it hot enough so it melts it's way through the plastic holding it in place....continually pull the head, and it will slide right out. From there, you will take apart the head and remove the metal rod/rivet and replace with whatever you desire the new head mounting system to be.

<agrees with Frenzy Rumble but, both ways have the means to destroy the parts. Just be careful no matter which direction you take and you'll be okay.