I presently ride a 1983 Yamaha Virago with a 920cc engine. I bought it because I wanted to learn to ride and it was a good deal from a friend. I thought I would always want to ride a cruiser type of bike, but I'm getting more and more interested in sports bikes instead. My main question surrounds engine size. I'm 6'1", around 210 lbs. I do a fair bit of highway riding, and would ideally like to be able to seat someone else on the back if need be. When talking to cruiser guys, they say, 'don't go less than 1k ccs on your engine size, preferably 1500 or more.' My requirements are listed above. I'm looking for something that's not going to tach out on the highway, so can I get away with a 600-700cc sports bike or should I keep looking in that upper range? Anything else you want to add? Thanks for the help.