On many BSAs I have worked on, I have always found that the splined clutch centres,(see photo) and also the engine sprockets will slide apart by hand, easily.
With my B44, they are both VERY tight.
The clutch took about 20 heavy hammer blows to get off.
The primary chain would not come off the engine sprocket, because of the closeness of the rear case casting.
The sprocket resisted all attempts to pull or hammer off.
I finally got the blowlamp on it, trying to avoid burning the chain. This was successful.
I have now polished the outside splines on the inner clutch centre, and used a dremel grinder to polish the splines
inside the outer part.
Now, the parts will slide together part way, then lock up.
It will take hammer blows to push fully in. I do not want to assemble like this.
How can this be???
Suggestions please.
Mick