Sometimes the tire will cup with age. I ran a Metz330 once and it started weebling real bad. I changed the tire out and no more wobbles. That Metz had about 7K on it. The Mag Mopus is known for tracking road grooves and getting real hard and cracky with age. You haven't said which bike you have. The Mag Mopus is oem on the america. If you have 10K on that tire, change it out and forget about it for another year or so as the wobble will not be there anymore.
PS: Also lift the front end off the ground and grab holt of the front forks and try to see if there is any play in the headset. Ensure the fork shocks are working right, and make sure your front spindle and pinch bolts are torqued to spec. Make sure the caliper is bolted up too.
