Electronic speed limiter worldwide applied? European CB1100EX owner here

[the_undecider_imp]

I'm willing to bet it's the huge top case. Empty or loaded, it will have an adverse affect on high speed stability. Extra weight on the back will lighten up the front end. Also, the air currents coming around the front of the bike and your torso will catch that top case and create either wind buffeting or could but pushing down on the top case somewhat like a spoiler on a car. I also don't think you can rule out the fairing creating lift on the front end. The reason sport bikes have such a pointed nose is to help create down force up front. Same goes for the ugly beaks on adventure bikes. The Road Comet is somewhat blunt in profile, so it might be lifting the front of the bike.