Don't take this personal, but it might be you. You were compensating on the twisted bars and now your not. Give yourself time to readjust to the new bar and see if the wobble works itself out.It happens at about all speeds but is hardly noticeable at 70mph. It just likes to weave on the road. The fork tubes are the same height and the wheel bearings are good. I put the old handlebars on because the other ones were tweaked a little but it is still the same.
The road question has some validity. The highways here are grooved and you don't really notice on worn tires. Put new shoes on her and she developed a little wander. Does it on my truck whenever I have them rotated.How fast are you traveling and are there grooves in the highway you travel? Also, can you give us an idea of how the wobble feels, when it starts and stops. More details surrounding your issue would be helpful. What condition are the front tire bearings? What condition are your handlebars in? If they are twisted, that could cause you to over compensate and produce a wobble in your front tire. Something else, are your fork tubes the same height in the tree? If one is higher/lower than the other, it might introduce a wobble.
Sorry for all the q's, they all came at once and wanted out, lol.