6 Spring Clutch sleeve identification

[watts]

I have 1952 B31 and 1961 M21

Being a little careless and assuming the clutches were the same I thought to combine the B31 and M21 to make one clutch for the M21 and fit a 4 spring to to B31.

There was an extra sleeve in the parts box now I do not know which is which.

All 3 are different.

B31 a barn find and complete presumably running before being stored and the M21 an incomplete restoration, which came with a box of bits.

I think the 3rd picture is an A one 42-3017.
But is 1 or 2 65-3873 they have the same depth to the taper from the gearbox unlike 1 which is deeper, but 2 fits on taper like 3.
1 does fit taper with felt water but definitely with. acorn one also.
I wondered is 1 for steel chain case, 2 for cast ally and 3 A models?
I assume they are not interchangeable?

I would be grateful for some help.

Or should just abandon it an fit a 4 spring or belt drive.

Thanks
Matthew
 

[watts]

Here are some extra pictures.

[neil1964]

Beware that I am not an expert but have had cause to investigate the B31/B33/Gold Star 6-spring clutch with the alloy chaincase.  What I cannot see on any of your hubs is the aluminium oil scroll that is an interference fit on the reduced section of the hubs.  (BSA 65-3833. Part number 13 on the Dragnfly diagram)
Does the hub back end sit in the chaincase adjuster plate plated brass?
Or is the M type different?

Looks like plunger versions should have the cork, felt and scroll collar?
Maybe someone more familiar with the plunger (pressed steel chaincase should comment?)

To determine whic hub to use I would fit your engine sprocket and then assemble the clutch centre with chainwheel aligned.  Use a steel ruler/straight edge to see which hub allows your primary chain sprockets to line up properly.  Then I suggest you use that one with new alloy oil scroll, cork and felt.  Only model that does not use the scroll is C10/11 from what I can see.

[watts]

Hello Neil

Thank you, I will take your advice.  I have the oil scroll just not fitted in the pictures.

The problem I have is that with the felt and cork fitted none of them really make what I would have thought is good fit on the taper, tightening them up tight may, but you can see from the photos how far they go but with the felt and cork seems to be a problem.

Thank you
Matthew

[neil1964]

The way those are fitted they look to limit oil wicking down the mainshaft/high gear route.
I've gone for the SRM oil seal/nut option in my needle roller boxes. If you are keeping costs down what you have should be fine. Main issue is oil loss from gearbox if you use a side stand lots.

[watts]

Hello

I did think about that, but I don't think they fit plunger models?

Thanks
Matthew