Vulcan 500?

[daveyg]

I've worked on a few of them, really thought they were a pretty sweet commuter bike, so when my buddy (new to bikes) found a screaming deal ($300) I had him jump on it. I helped him get it running, (very thorough carb cleaning, oil change, A/F tuning) he took the local 3 day long bike training course and started riding to work, and he says he has difficulty keeping it around 70mph on the freeway, and 2 weeks in and he has barely averaged 30mpg?! Compared to the 50-60mpg guys on the Vulcan500 forum are claiming! Now he isn't a small guy, 6'4" and 250+lbs, but 30mpg? It's got ~30k so maybe it really needs a valve adjustment? But it runs like a raped ape at slow speeds (under 50mph) with me (150lbs) on it...

I've been scouring vulcan500.com and all I can guess is it must need a valve adjustment and vacuum sync, but would those alone cause half the expected fuel mileage?