Good to know the outer race is fitted fine, that's half the battle.
Sorry to say the BSA Cush Drive assembly comes up time and again, along with the hassle of shimming the crank.
I reckon having a bearing inner that is "easily" removable is preferable to one that is a drive fit on the crank. This latter stands a good chance of being wrecked as you attempt to draw it off again to amend the shims. For that application there are variations in bearing type, one sort (NJ Series) leaves the rollers in the crankcase, allowing easier access to the bearing inner. NUP Series is similar, but with a demountable flange which supports the outer ends of the rollers and eliminates end float. A deep groove race is also used by some folks, cheaper and no crank endfloat as featured on the Longstroke A7, and BSA went back to a ball race in the early Unit models, A50/65.
So a good plan is with the bearing inner race on the crank, assemble, and bolt the cases together. Add the spacer, drive sleeve and retaining nut. No need for cush spring or sprocket at this stage. Spacer is not required on Plunger engines. Then tighten down the big nut, this will push the drive sleeve against the bearing inner, which is now nice and tight up against the crank. Leave all in place, then you can measure the float and select shims as required, not forgetting to estimate any difference a smear of your favourite jointing will make.
Now we come to an aspect which divides us. Any rotational movement between the crank cheek and the inner race will result in the shims being rubbed away, as evidenced by bits in the sump. So how do you prevent this?
Various views hold, from Loctite to peening crank and race, selecting the tightest race you can find etc. But if you were a shim under a load exerted of some 70 Ft LBs (accepted ball park figure) applied to a big nut, you would certainly not be going anywhere. BSA did not suggest a figure, "really tight" is what the books imply.
All this has been mooted in the past, but in essence the crank nut has to be done up tight, homespun peg spanner or commercially available tool.* Also the drive sleeve must be free to slide towards the crank web as far as it can go. A crank which has had a loose nut can end up with wear to the splines roughly half way along, a distinct step which will hold the drive sleeve away from tightening down fully against the inner race. Locking compound on the inner race is belt and braces, but a gut busting torque on that crank nut is really all that is required. Certainly compressing the cush spring takes some effort, but the torque setting takes this into account.
Lots about this on the Forum. Split pin is there to stop a loose nut machining a neat hole in the primary case, not to secure the nut which should end up a few threads below the split pin hole. Hammer and punch is the hooligan method, wrecks the nut and invariably never tightens the assembly enough. Loctite on the nut also recommended.
Swarfy.
* Peugeot Ball Joint socket.
