Here's what I got:
- Takeoff from a standing start at about 3,500 RPM
- 35 miles per hour at about 6,000 RPM
- 45 miles per hour at about 7,500 RPM
- 55 miles per hour at somewhere between 8,500 and 9,000 RPM
The speeds above are as measured by my GPS phone speedometer app, not the "optimistic" speedometer.
The RPMs above are as measured by the bike's tachometer (in addition to questionable accuracy, the numbers are rough -- it is a digital needle gauge, not an exact numerical display gauge).
Environment definitely affects performance, and I suspect it does so more vis a vis small-engine, light-weight bikes. Today is a wet and somewhat windy day. On a dry (better traction), windless (nothing pushing the bike in directions other than the intended one) day I'd probably go a little faster with a little less engine strain. I maxed out at 55 mph and it was a crawl getting from 45 to 55; I can get at least close to 60 when conditions are right. My recollection is that 45 miles per hour is usually more like 6,500 RPM.
Anyway, once the work gets done, I'll have numbers to compare to.
Speaking of that phone app, I finally found a handlebar phone holder (not an affiliate link) that accommodates my thick-cased phone and doesn't seem to vibrate out of place, etc.