Play in headset with no upper bearings on a tandem bicycle I have a half recumbent tandem bicycle. The front fork headset (under the front cyclist) is loose: I can feel some play when I put the front brake on and try to move the bicycle front and back. I tried to tighten it with no success. I disassembled it and was surprised there was no upper bearings. Could this be normal, given the bicycle geometry (not much clearance between the front seat and the headset and no need for a stem) ? I found some kind of seal which was torn out. Could this explain the loose headset ? Any help would be appreciated.

NB: the bike frame is from Bilenky (viewpoint) but the set up was done by another company.
A single bearing race really isn't very good at resisting torque perpendicular to its axis, so I'd be surprised if there wasn't meant to be a set of bearings in the top. Even closely spaced sets of bearings aren't great in that regard. Unless there's a special arrangement inserted from below, the lack of a top bearing would be likely to cause play, and possibly damage. The lower bearing should be checked in any case. The load on a tandem is quite high so I'd expect a robust design using the full available steerer tube length.