Handlebars are either too loose or too tight

[Knoob]

Hello, I've had my bike from teenage years in the garage with the wheels off for a few years now.
Put it all together and instantly remembered why it was in storage. The handlebars either move without the wheel turning or the handlebars get REALLY hard to turn (with the wheel ofc). Its a matter of maybe a quarter turn on the top bolt from loose to tight, there's no inbetween.
I think when I was younger I pulled a wheel bearing from somewhere in frame between the handlebards and the forks, but cant seem to the get forks out anyways.
Any ideas or sugestions?
Its a Berg Stuka 9.1 or 9.2 (Probably 10 years old now but just so you can google a reference picture).
If you want photos I'll snap some , just let me know of what!
Cheers

[ReapThaWhirlwind]

The headset needs to be taken apart and checked. There's supposed to be a caged or sealed bearing on the top and bottom. That's the first thing to check. This issue happens one of two ways. On a threaded fork setup, the locknut is over-tightened on the top. This causes seizing of the fork. In a threadless setup, the distance of the top cap is incorrect and/or the top cap screw is over-tightened; producing the same problem.

For a threaded setup, the locknut and threaded top race should just be a little more than handtight.

In a threadless setup, the torque should be about 8~10nm.

[GirishH]

Hello Knoob, thanks for starting this discussion. Interestingly my bike is behaving the same only going through a disassembling-assembling because it had to fly back to the US. Before that, I rode it for some 1500 miles with no issues at all. I guess, I will follow ReapThaWhirlWind's suggestions and will keep you posted.