Are you saying you're uncomfortable with your speedometer only going up to 85mph, or are you saying you're uncomfortable with the fact that your bike won't go fast enough for the interstate?
If it's the latter, then your bike isn't running anywhere near top condition. You should be able to do well over 100 on that bike if you wanted to. The way you can change it is to do a full tune-up to get the engine running the best it can in its current configuration. If after a tune-up, and you've verified the carbs are all clean and working properly, and the engine still won't run like it should, then there may be bigger issues.
As far as the bike sounding "too wound out" at higher speeds, this is usually a matter of rider perception. If you're used to the sound of a big V-twin, then a 4-cyl bike will sound like it's running too fast for a given speed, but that's just the nature of a high-revving engine design. A 4-cyl engine of comparable size has to spin much faster to make the same amount of power. That's just how it is, and it's not hurting your bike. It was designed to rev high.