Speed wobbles at 65mph and higher

[tomtom7]

Took the gz on the freeway for the first time today. The bike managed better than I expected, at least in the slow lane, but I noticed speed wobbles once I hit 65mph. Is this just because of the low bike weight? Or do I need to adjust something (e.g., shocks)?

The best way that I can explain these wobbles is that the bike makes tiny side to side movements. It wasn't difficult to keep it straight, but it didn't feel stable. I don't feel anything like it below 65mph.