Agree with above posts - The Yamaha XT600 series of bikes (all models) are not designed for riding at those quoted speeds.
My bikes cruise happily all day at 60 mph max. Higher than 60 mph they feel unsteady. Although it's possible to touch the ton just... (flat on the tank with assistance of the wind on a long straight), it's not to be recommended for longer than a few moments!
Ride your bike within it's designed safety margins (max 60mph) and all will be well. Tank it over this speed and be prepared for a spill or worse!
The XT6 is an awesome economy RTW bike nothing out there will beat it. It's reliablity and simplicity record is legendary.
Where these bikes do excel is in town on B roads (relaxed countryside riding) and on light trails. Take them onto the motorway and they are less capable. A single cylinder bike without wind protection is never going to perform well above 60mph. I ride my bikes in the countryside (summer only) at speeds averaging between 40 - 50 mph and they take some beating. I like the high riding position because it allows you to see over hedges etc... I also enjoy the "grunty" low down torque the single cylinder XT engine produces...
Lastly if you ride at those speeds, your bike (and you) probably won't last very long.
If you are a speed demon then get something that will put up with that punishment and give better wind protection. Sounds like you need to get yourself a twin cylinder (or more) trail bike instead...
Some modern bikes (sports/tourers) are very capable at speed but you must ride well within your riding capability
in order to stay in one piece. Never forget the country road killer - their might be a slow tractor or broken down car around the blind bend....
Triumph Bonneville 800 (2004), Yamaha XT600E (1999), Honda XBR500 (1986).