I think the R65 gets compared too often to the 1000 cc bikes,which are made for high speed cruising.
I've had my R65 since January, 1981, and just passed 80,000 miles on the odometer.
When the national speed limit was 55 mph here in the US, the R65 does pretty good on the highway.
Here in Arizona the speed limit on rural interstate highways is 75 mph, and while I have no complaints of how the bike handles, up to the 85 mph limit on my speedometer, there isn't much left in the engine power department , if you need it.
Fuel mileage gets down to the mid 30's at these speeds.
My personal observation, is that the engine doesn't sound 'too happy' at 80, seems like 65 mph is where the bikes feels good.
You get this bike on a nice twisting turning road, and that's where it is in it's element.