1972 Commando 750 Gearbox Cradle Spindle Modification?

Restoration continues on the formerly hot rodded 750. Noticed something while preparing the gearbox cradle for reinstallation.

I can't find any revision of the gearbox cradle that matches the welded on nuts. I'm assuming these nuts are to accommodate bolts to 'pin' the spindle? Similar to the swingarm collar modification?

Interestingly, the spindle that was in place did not have the machined flats I'm seeing on replacement spindles available.

This was a mod done by the PO

You have a "added" bonus

Awesome, thanks for the quick replies guys!

Cammy66 said:

Interestingly, the spindle that was in place did not have the machined flats I'm seeing on replacement spindles available.

Click to expand...

Yes, the spindle with the flats (and no central location hole) was a later modification introduced on the 850 Mk3 'cottered' cradle...
https://andover-norton.co.uk/en/shop-drawing/137/swinging-arm-suspension-units-chainguard
...however, a cottered cradle is now available for pre-Mk3 models so the latest spindles have the central threaded location hole and flats so they can be used with either cradle type.
Also, note there are two lengths of spindle and yours would be the earlier longer type.

L.A.B. said:

Yes, the spindle with the flats (and no central location hole) was a later modification introduced on the 850 Mk3 'cottered' cradle...
https://andover-norton.co.uk/en/shop-drawing/137/swinging-arm-suspension-units-chainguard
...however, a cottered cradle is now available for pre-Mk3 models so the latest spindles have the central threaded location hole and flats so they can be used with either cradle type.
Also, note there are two lengths of spindle and yours would be the earlier longer type.

Click to expand...

Interesting about the cradle for pre-MK3. I bought one years ago, I think it might have been for a MK2A or similar era.
I looked at the Andover site and didn't see a sub for the cradle on pre MK3's, just that the cradle was unavailable.
Is it somewhere else?

Deckard said:

I looked at the Andover site and didn't see a sub for the cradle on pre MK3's, just that the cradle was unavailable.
Is it somewhere else?

Click to expand...

Both the standard cradle and pre-Mk3 modified cottered cradle are currently "out of stock" at AN.



RGM

I was tempted to weld nuts on a 1970 cradle that is being used for a complete restoration. Welding tends to warp steel so the cradle would have to be straightened afterwards. Instead I ordered split collars to go completely over the cradle. Instead of just drilling the cradle I threaded the split collar after it was mounted on the cradle so the threads (1/4-28) go through the collar and the cradle for a stronger deeper thread. They are marked left and right so I can get them back on correctly.