lots of possibilities. tire out of round, bead not seated properly, bent rim, unbalanced tire, wheel loose... not properly torqued/forgot cotter pin, front and rear wheels not aligned, wheel bearing (noise). damaged shock dampers between wheel an hub could make a wheel wobble. also ossilating fork vibrations some bikes are apparently susceptible to.......
i seem to recall certain brands of tires on certain bikes can cause the fork oscillation issue at high speeds. very dangerous. how did you get out of it? did you have to bear down on the front end while letting the engine brake itself ?
Yes have a good look at the bead seating all around on both sides... I installed and balanced my Metzeler Roatec Z6 tires myself, and they're perfectly smooth and solid up to a sustained 120 mph. Is it a side to side wobble (tank slapper), or is it more of a jackhammer shake/vibration which would indicate poor balancing?
Do you have an oversized windscreen and/or handguards? I had to lean my 2007's tall windscreen backwards as much as possible by modifying my mounts, which completely cancelled a genuine mid to high speed wobble I had.