[Smaug]

A Burgman 400 will be fine for up to about 75 mph. It can do 85 if you push it, but it's breathing hard. (and I'm only 175 lbs.)

For around town riding, city and suburbs, it is pretty much effortless. Tons of torquey power, up to 60 mph. If you're in a tight city area or won't go above 55 mph much, you'd be better off with a 200, I think. They don't have as much clutch slip before they really get going in earnest. They are also more nimble and easier to handle at parking lot speeds.

Last thing, and please don't take it badly: lose some weight. It'll make everything better in your life. Look into The Perfect Health Diet. It's pretty easy to follow, and you still get to have some healthy carbs. (white rice, starchy vegetables like taters) Oiive and coconut oil for cooking, beef, lamb and duck fat are all encouraged too. Pork and chicken/turnkey are considered neutral. Buy the book, it was written by a husband/wife pair of PhD researchers and everything makes sense to me. (except why white rice is OK but white bread isn't)

The Burgman 400 has preload-adjustable rear shocks. You'll want it on the firmest or second to firmest position, so that you're not bottoming out.