My friend is looking at his first bike, and he's looking at engines in the 500 to 900 cc range. I don't know much about the street series Harley's, would a new rider outgrow a 500 after a season or two? Do they have acceptable power/torque for general riding, including interstate usage? He's average build, about 6' 190lb.

Thanks in advance for the insight,

 

the 500 is good for a starter, though after a couple of years he might wish he got the 750.

i test rode the 500 before getting the 750, and settled on the 750
i use it for commuting to and from work ( 50 miles a day, 95% freeway) and it easily manages freeways and speeds/power needed to overtake/accelerate.|

speed wise, i have had 105 mph out of it and it didn't feel stressed to do so.
weight wise, very light.. easy to flip around traffic
gas mileage, 55-60 MPG ( 3gal tank)

 

The 500 was tailered for noobies. After a couple years (or >5000 miles) he should be ready to move up.