Hello,
I am building a Winow TT-119 bike and I am wondering if the stem gap is normal or if I did something wrong.
I tried swaping the bearing but it get worse. Same with the metal piece that goes on the bearing.
Thanks !
Torque it to spec and measure the gap. The metal piece you're describing, is that the compression ring? I might be mistaken, but I also don't quite see a headset top cover. It's there to keep dirt out of the headset, but with a gap like that, I'd recommend packing a bit more waterproof grease (eg. marine grease, dielectric, etc that repels and lubricates).
The bearings should be quite flush within the headset, indeed. Did you check if the bearing is placed in the right way? The conical part should sit comfortably in the headset, and do check if your fork has a crown race. Some forks have an integrated one that comes with the respective headset, which could be why the gap is there and got worse with a different bearing. The compression ring should sit within the top bearing, but all bicycles will still have a gap on the headset, as it allows pre-load and rotation. If it was 0mm, then the preload would be set incorrectly and you wouldn't be able to steer your cockpit.
Edit: Just saw the other images, oops. (The stuff I've written is still relevant though to the topic - edited my message for better clarity).