Originally Posted by LandPirateMBC
I'm currently commuting daily on a 1978 Suzuki GS400. It's got enough power to pull me at 70- 75mph on the hwy without crazy vibrations or struggling too much , six speed tranny and has never failed me. Yet It just doesn't seem like a bike i'd want to spend more than a hour or two on the hwy with.
This is exactly why I would suggest you go with a larger displacement. Unless your current GS400 is a european spec bike, it's 37 horsepower (in the US) measured at the crankshaft, like the Savage's 32 hp. You will be loosing a pretty big percentage of total power, and a gear too. So you'll have less gear/power overlap. In short, performance will be noticable lower.
If it's a cruiser for longer trips on the highway you're looking for, I'd suggest a 40 hp Yamaha/Star 650 V-twin as an absolute minimum, and a Honda Shadow 750 or Kawasaki Vulcan 750, 800 or 900 would be a big step up from there.