I stood still on the highway last Saturday.
After 3 hours I got home and took all apart to find the clutch mainshaft nut loose. I was afraid that damage took place on the mainshaft as the whole clutch basket was loose on it. To my surprise everything was smooth and ok. Cleaned thoroughly the tread on the shaft and tightened the nut back again with some Loctite.

Problem: The clutch operating arm is now sticking out much more then it was before, forced so by the pushrod. I have checked the later which is in a like new condition. I would say sticking out 20 degrees instead of the before less than 10 degrees. I thought oh well, and tried to operate the clutch. It is functioning ok, but I cannot engage the gears. I took the primary chain case off again (cursing like an old farmer). Found out that while pulling clutch lever the whole basket is a bit loose on the mainshaft (or is it the mainshaft itself loose inside the gearbox?) and a tight fit while not pulling clutch lever. I am afraid that the damage is inside the gearbox. It seems as if the whole basket/shaft thingy has moved to the right side. I plan to take it out next week.
I'm now going to weep in the kitchen a bit.
Have a nice weekend all.

Hi Michael, sorry to hear your having trouble, reading your description I think you should check your clutch roller bearing.

Probably some wear has taken place there which explains the rocking clutch assembly. This wear might force the inner basket more to the righthand side, this could explain the position of the clutch operating lever. Good luck, Michiel

Thanks Michiel.

BTW, here's a short movie from yesterday night:

https://photos.app.goo.gl/OIoWyq1QTEUsPWa23

Hi Michael,
i had the same problem a few years ago.
Also no harm done.
It is very well possible that the clutch want't tight in the first place and then slowly came loose.
Now you did tighten it better, it the push rod will move up a bit to the right. Maybe its a bit to long, now.
I would adjust the whole thing once or twice more and give it another try.

The chances that your clutch bearing or gearbox is damaged are rather small.

Hello Mick,

I also thought so, but that does not explain why any gear can't be engaged...

Michael, you mentioned that
You "Found out that while pulling clutch lever the whole basket is a bit loose on the mainshaft"
It looks quite normal to me. maybe when the bike was new it was not like that,
But I have 3 BSAs M20 and M21 and the basket is a bit free in all of them, with no issues in function.
There was a local conversion I saw, of replacing the rollers with a closed bearing,
Which apart from not suffering from the fact that most people run the case dry without any oil,
Also made the clutch assembly more stable and not rattle when the clutch lever is not pressed.

Noam.

You are right about that, Noam, forgot to mention that.
Its perfectly normal for the clutch to have a little play when the lever is pulled.
No reason for concern.
Let us know how you get on, Michael.