That's a lovely picture of what I think is a BSA v twin, OHV. I notice the low "c" number and the lack of a blackout hood, plus the lack of a rider's helmet - so that would put it at about 1939? Does anyone have any more insights about this?
"BMM" series registrations were issued from December 1934...I can't see anything to pin down the date of the photo accurately. Service Dress and '08 webbing was commonly in use in the UK up until the outbreak of war. The bike looks well used, probably a year or two old at least...
Thanks, Rik and Ron, for such a quick and informative reply.
It's a handsome bike and it certainly seems to be exactly what you say. I wasn't even aware that the Military had different labels for the Pre-war BSA 500cc bikes, and that those labels were different from the commercial designations. Fascinating. It's always an education!
I think he may be an Argyle and Sutherland Highlander, his white blue signals armband is very faded and is that an 08 large pack he is using to carry messages?
There were problems with premature cylinder wear in the 500cc V Twin...BSA specified a particular oil for that engine apparently...
I've read there was also a period where this problem occurred in other models in the mid to late 30s and hardened liners and alternative piston rings were also employed in a bid to solve it...I've come across the hardened liners fitted to M20 cylinders..
I've never got to the bottom of it, or defined exactly how long the problems lasted. I can't really understand why the problem suddenly appeared...After all, BSA and others had been making basically the same cylinders for years...Ian
That's a really interesting point about the cylinders. I know that the Matchless v-twins 1930-38 had an internal oil line to the base of the cylinders, and that Indians had an extra oil nozzle outside the cylinders in the early days, to augment the splash system. J.A.P. engines also tended to favor an extra oil line from the Pilgrim pump to the cylinder base. Indian in the 20s and 30s created their crankcase castings such that the connecting rods passed through a small opening, and the remaining 'blanked off' part had holes in it, usually 6 of about 3/8 diameter. The theory was that the oil vapor would be sucked up the cylinders more readily than with an open hole. It seemed to satisfy Indian.
Manufacturers found that with a single the regular suction created by a single ascending piston would assure adequate lubrication. Now, if you have a v-twin that suction would be upset, wouldn't it? Two pistons at different places in their cycle would disrupt this method of oiling. With a parallel twin one wouldn't have this problem, I think.
Indeed Lex and her fingers are probably too short to reach anything, but small hands inserted into anything with springs and latches all too often ends in tears !
Here the names of the children sitting on and around that motorcycle
Willy Van Droogenbroeck, Adolf Van den Brande, Herman De Neys en Adolf Heymans. Vooraan: Magda Van den Brande, Irène Guldemont, Hedwig Van den Brande en Agnes Heymans.
