Topic: CB750 drive hubs: later circlip version better holding clutch basket?

[PeWe]

I have just found out that the drive hub I intend to use has no groove for circlip.

This older hub cannot be used with later clutch, or?  The circlip will keep axis in place, gear will slip without?
Later hub with groove for circlip has lonhger axis.
The earlier without groove seems to fit with hub in same position.

EDIT:
Washer photos found on the forum
I think that the wider 25mm washer must be used with the drive hub without circlip groove. Later hub with groove and criclip use the thinner washer.
The earlier drive hub without groove and shorter axis - wider washer. This mix should work if this worked earlier. One question is why the circlip was introduced from K6 and earlier F.

[PeWe]

I have investigated more about later with circlip and slim spline washer or earlier with thicker washer only
The main shaft 23210-300-000 is same on later version (K6) and earlier (K4) so that makes no difference.

The photo with no circlip drive hub axis show that the earlier thicker washer most likely will fit will very well and do the job as the circlip with slimmer spline washer do.

Using a later complete clutch with outer basket should work on earlier engines. I mean the later clutches from 1975 F and K6.
Clutches after these got double metal disc and deeper clutch hub, matching parts with longer fingers and other clutch cover...more to add.

- Anyone that know why the circlip was introduced?
The old design with thick spline washer only did not do the job holding the outer basket as intended?
When the entire clutch is mounted nothing can move out of position anyway, or?

I'm worried to take a chance and later find out that I must pull engine and open it completely to replace primary hub  with later circlip version or only replace the entire clutch without pulling engine, insert the earlier K4 version.

- Next is which clutch that has best grip, earlier like K4 or later, or no difference?