Troubleshooting help: Dyna weave

[scar04]

So, over the last couple of weeks, I've noticed what amounts to a weird weaving sensation on the dyna glide. It feels kinda like I'm riding grooved pavement when there is none. The roads are relatively smooth and I can't figure out what it is. It's almost like I'm playing with the handlebars. I don't think it would be the steering head bearings, bike is just shy of 10,000 miles. I'm wondering if it's that the tires are cold when I'm riding. My other thoughts are I've tossed a wheel weight somehow, but don't know how I could figure that out without a wheel balancer and a friend with a stand. Might be my tires, which have tread left on em, could be at the limit of their temporal life span. Just trying to narrow it down. Anyone ever encounter this on your bikes, or heard of it on dynas? Something is just feeling wonky on it, and no, I am not just looking for an excuse to trade her in on a newer toy.