Another B31 speed question!

[KernowPete]

I have a 1953 B31. I tend to stick to back roads but often see 60 -65 mph out of it. It's not been restored but is in good mechanical order with good oil. It so far doesn't seem to complain. It's on standard gearing but 3.5 rear tyre. What do others ride theirs at? This is more about a comfortable limit with regards to mechanical sympathy than what the bike can do. I've not had a long stroke single before and think I was initially guilty of lugging it at low revs too much (as it's fun).

[yellow B31]

I have a 1949 B31 on standard gearing and in good mechanical order. On back roads I find a speed of just below 50 MPH before a mild vibration sets in to be the most comfortable.
With respect and not a criticism of your riding style if I wanted to travel at 60/65 MPH I personally would not use such a bike.
In the 1960's I ran Norton ES2's, 500cc, as my only transport and 60 MPH on the open road was my limit for long term mechanical reliability.

[Derek996]

I currently have a B32 Competition, same engine as B31, and although it would go faster I'm happy to limit it to around 50-55mph. Back in the '70s I had several B31s and although I could get 60-65mph, 70 at a push, they didn't last long. Admittedly, I was a lot younger then and rode a lot harder. If you any mechanical sympathy you should try not to exceed 60mph too often.

[KernowPete]

Thanks people - that's pretty much what is was expecting to hear and will back up the angel on my shoulder telling me to back off. A bit challenging when a nice quiet stretch of backroad lies ahead! Anyway I shall endeavour to treat the old girl with the respect she deserves. Runs like a clock, very little vibration and never complains so I'll try and keep it that way 

[neil1964]

I remember 60 being the sweet spot on "55 B33, ie local A roads being in traffic flow. Often overtaken by white van man and Audis and not enough in reserve for overtaking anything but a dawdler. 
I'm in the same situation nowadays with my daily driver (52 year old Landrover SWB station wagon - with overdrive- lol) so I stick to B roads and shorter A roads.   Back to bikes i tried replacing that with touring spec ZB34 with 30mm concentric and 20T engine sprocket was a good step forwards.
Brakes are much more of a limiting factor for me and the SLS front brakes (7 or 8") are simply not good enough for anything but gentle pootling.
I've gone 600ABSAF with Nova 5 speed (road) box and Phil Pearson TLS front brake and can cope with most conditions (licence notwithstanding). The other motor is sitting waiting to go in my CB34 competition frame back to 19T engine sprocket for back lane pottering.

[yellow B31]

Interesting point neil1964 I wonder whether the stock B31 would pull a slightly higher gear or would it spoil its flexibility?  Mine will run smoothly at 25mph in top if required with a bit of retard.
I live in East Anglia with its exposed fen land and its occasional strong winds. Was out yesterday on the bike and it handled a 3 mile long straight road into a good head wind with little difficulty.

[Derek996]

I don't think it will pull a higher gear. I have had the B32 for a couple of years and I'd wondered why it struggled to do any more that 55mph even with the 9:1 piston it's fitted with. I was happy enough with that speed for a 76 year old bike but would have liked it to get there a bit quicker. It turns out that it had a 19t engine sprocket giving it the same gearing as a 500cc B33. No wonder it lacked oomph! Over the winter I've fitted a 17t sprocket although I did ponder over fitting an 18t. I haven't had it out on the road yet but I expect to see a marked difference and probably a lot more vibration too. 

[idie]

The vibration won't be any worse it will just move down the speed band.

[Fraz]

My '54 B31 will do 65 flat out but it's more suited to 40 to 45mph (for mechanical sympathy)
Myself however, I like cruising around at 30 to 40mph - just so I can hear the exhaust and enjoy the ride