I've only seen this once in my 50 years of BSA ownership and I hope I don't see it again....This is what happens when the gear selector dog breaks up at 45 mph...Bent shafts and other incidental damage to the gears etc was also present as can be imagined and the inner cover was also cracked/broken around the bearing...It's fair to say the gearbox basically exploded...Ian

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

Did some one exceed the 15 horse power limit?

That could have hurt!

At least the bits are easy to get.

Mark

email (option): pes.sales@btconnect.com

It's from a 600cc M33 that I sold to a friend about 15 years ago or more....He doesn't drive it particularly hard though, he just likes the stronger bottom end and mid range for his trip to work etc.....
The fact is, I suppose, that stressed parts don't last for ever as we tend to think they will...Much of what we are using is well beyond its designed lifespan after all....Ian

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

Did it lose drive or lock up ?

Was the skid mark in the underpants longer than that on the road ?

I was very interested to see this as after 60 years of messing about with BSA gearboxes of various types this is the first time I have seen a major disaster with an M series box. I have seen several very worn gearboxes with bad bearings particularly the sleeve gear bearing and others with a lot of metal bits floating around in them But never any thing like this and I have always said that the M series box despite being slow with its gearchange was a wonderful thing (and the clutch too ) to have put up with what they were subjected to during the war. Very interesting. Regards to all from Dave Barry.