Conditions
Have you tried wobble testing on various, different roads? Asphalt, concrete? Are you sure the roads you ride on are not a factor?
Wind a factor?
Bike
How many miles on the bike?
Has the bike ever been laid down/accident/repaired?
As toon mentioned, is the bike properly lowered to maintain geometry?
Tires
Why did you replace the tire (assuming to address the wobble)?
Did you (or the shop) inspect the front tire which was being replaced for unusual wear, if yes was their unusual wear?
Did you replace the rear? Why? If no, why the front and not the rear?
Maintenance
Have you checked steering head play?
Have you performed maintenance bolt tightening, including steering stem head nut?
General Comment
It's not unusual to get some wobble when releasing the handlebars at speed. Riders aren't really supposed to do this, motorcycles are not designed to operate in this manner. Although lets face it most riders do from time to time (I admit, I do). The simplest solution if there are no clear symptoms (loose steering, unusual tire wear) other than finding the exact cause is to not let go of the bars.
My old bike had some wobble sometimes when I let go of the bars. I never had any problems with tire wear or anything. But I learned what speeds to avoid letting go of the bars for a quick rest. But I could also tell prior owner(s) had probably laid it down (gently) and the forks/triple tree were a tad tweaked. I could tell left clip-on was closer than the other side (probably a couple mm). Rode the bike 13,000+ miles, never had any safety issue or whatever (have never been down actually)
Hope this helps.
* Last updated by: VicThing on 9/5/2014 @ 3:25 PM *