When I attended the BSAOC rally in 2006, held in Massachusetts, there were two forlorn chaps with their M20 engine disassembled and spread out on a sheet displaying the broken con rod. As I remember the story, they shipped their WM20 combination from the UK and were heading to the Sturgis rally when the rod failed somewhere in the vast midwest. Local enthusiasts got them to Massachusetts, where they were awaiting the delivery of a new rod. BSA sidevalve models were never plentiful in the US and they had some difficulty finding parts. This was long before I had any interest in the M20 and could not oblige them.

Anyone know more details of this story? Are these chaps on our list?

My take-home lesson at the time was respect for metal fatigue, even in an under-stressed engine. But what is the full story?

Jeff Bandola

email (option): jjbandoo@aol.com

Rod failures in themselves are pretty rare on an M20/1. I've seen one and heard of a couple more in the 35 or so years I've been messing about with these motors.
From that limited experience it seems to usually be the case that something else went first and THEN the rod broke...for instance a piston siezure.
If it was two guys in the vast expanses of the midwest on an M20 sidecar outfit there is a good chance they were driving hard on a heavily laden bike....it'll be interesting to see if any more info turns up.
Two friends of mine did the London- Beijing Rally on an M21 outfit...down the Silk Road into China and through the Gobi Desert. 9,000 miles in six weeks.
Some days they rode for 17 hrs!
It was so hot it burnt the transfers and laquer off the petrol tank but the bike ran beautifully...I guess it's down to the preperation of the bike a lot of the time...Ian

email (option): ian@wright52.plus.com

That would be Geoff and Sarah who only live a short distance away from me near Melton Mowbray in Leicestershire. Geoff is a very knowlegable chap who has a few M20s to hand. Not much to say about the misadventure but it seemed to him that it was only the conrod that was to blame and not anything else as Ian suggests. He also had to have some crankcases shipped over as well as a conrod but they soon had the bike up and running and were able to carry on with the rally riding I think after only two weeks waiting for the parts. They will be there on the John Bull rally in Belgium at the end of the month so I gather.

Well it can happen...I am constantly fascinated by just what can be achieved with a 60-70 year old machine and the degree of reliability still obtainable.
But every so often some component or other will decide it has reached retirement age!
....Ian

email (option): ian@wright52.plus.com

Says it all about what British Industry produced in days gone by I think and it amazes me too. My fascination however is the sheer simplicity of how the whole bike is put together and is largely manageable by most average DIY engineers and with very basic tools.