In Pennsylvania, the "hardcore" Harley guys (people whose entire identity is wrapped up in their motorcycle) won't wave to another biker unless they suspect that it may be a Harley. The funny thing is, it's getting harder and harder to tell if an oncoming bike is a Harley nowadays--but they definitely won't be waving to the Vespa, or the guy on the gixxer.
Now that's the "hardcore" guys. Most of the RUBS will wave, (although here it's RISURBS (Rich Suburban/Rural Bikers), haha. Anyway, no matter the Harley guy though, they always seem to be of one mind about the type of wave they offer, which is the "arm-straight-down-to-the-side-at-a-45-degree-angle--with-hand-motionless" wave.
A couple of years ago, my brother-in-law got fed up with the "I'm too cool to actually wave to you" bikers, so any time he gets that downward, slack-armed "wave," he waves frantically at them like pee-wee herman. That's one way to pop the ol' "cool bubble," lol.
And littlebill, I have to respectfully disagree with your assertion that OCC-type bikes shouldn't be lumped in with Harleys. They all share common engine architecture, and the majority of S&S productions retain the exact (or similar) outer dimensions, so that even some of their biggest engines can be shoehorned into a Harley frame. It's the same with other engine suppliers like Revtech. The riders are cut from the same cloth as well (in your story, literally, haha), so why differentiate? It's all a variation on the same theme (low, raked-out, fat tire, high price), which is why a lot of bike shows are a yawn. I'm glad there are guys like Motus and Confederate shaking things up a bit--redefining what "American motorcycle" can mean.