I've never ridden two up on my '58 R26 because it has a solo seat. Having said that, my R26 seems quite comfortable at 40 mph. On the plus side, I've never gotten a ticket riding through a school zone!
But seriously.. once you get her going.. provided you’re on a flat road or significant down slope, maybe 40-50mph.. but the singles aren’t exactly great for 2-up riding. Now if you weigh 100lbs and she weighs 50lbs, you may be able to grab a bit more speed but I’d steer clear of the highway regardless of solo or 2-up. My R27 will do 60+ if I really ask her to but she’s much happier between 30-50mph.
I was considering taking one on the nest Chase. Roughly 2500 miles over 10 days. Need to average 40-45 mph to be reasonably competitive, I'm 150 plus 30 pounds of gear. Did very well on my R51/3 last year.
That sounds miserable on an R26 or R27 but the R51/3 sounds like a terrific choice. If it were me, I'd take that bike again this year! Why mess with success?
So what is the Nest Chase? I'd love to hear more about it.
In 1970 I rode solo from Cologne to Vienna on my R26 (1000km) and after a short holiday back again with my girlfriend on the back. Both trips were non-stop (bar refuelling and meals) pretty well full throttle all the way. Downhill up to 130km/h uphill as slow as 70km/h and on flat road maintaining 100km/h both solo and two-up.
At the time that was my daily rider and I did lots of long-distance tours on the autobahn.
I am currently rebuilding an R26 and am amazed at the size of the bearings and parts in the engine, transmission, and rear drive, especially when you consider the relatively mild horsepower output. And the measuring of clearances and shimming for most moving parts makes me wonder how they ever built them on an assembly line. I am not surprised that you could run it wide open throttle indefinitely if everything is mechanically sound, properly tuned, and good oil. I can't wait to get this old bike back on the road after its 30 year storage!
Jim