1. As far as fuel consumption is concerned, its not that far off, there is a fair amount of town riding, blasting down the dual carriageways (up to 80mph), and filtering through stationary traffic on a busy Friday evening. So I am not concerned. Its certainly not a steady 56mph on the slab - for which the R100 would return 49 mpg at best when new, and that is UK gallons not the smaller American gallons - 40mpg for that.
http://www.bmbikes.co.uk/bmwmodels.htmR65 is another matter, up to 61 mpg UK, 51 mpg US Gal. Not that I get near that. But I get more from my r65 than for my R100 as you would expect.
2. Fuel is 95 octane unleaded. Not sure about the amount of ethanol.
3. I am curious about the reference to a Harley, and somewhat hurt