Allen Key storage? Hmm.

[Lobo]

.... servicing the old girl today (😱) and thought, “eh up, what’s this all about?”  Am I missing something obvious folk? (at the rear top side of the gear casing CB750K2)

[K2-K6]

I don't know for sure,  but always thought they were there to check casting integrity,  alloy mix etc.

By making them intrinsically hard to get a fine resolution of shape, they seem to show characteristic of casting flow, temperature etc.  If they are placed at most extreme displacement from cast entry points they'd give a quick "go-no go" assessment of casting quality before going further down production line to machining.

Presumably,  if that's true,  they'd be chucked back in to melt for the materials to go round again if they displayed obvious failure.

[Lobo]

Wow, totally plausible, thanks. Possibly missed a trick though in not casting the letters HONDA versus Allen key holes?

[K2-K6]

Wow, totally plausible, thanks. Possibly missed a trick though in not casting the letters HONDA versus Allen key holes?

If that's the true origins it may be just standard issue foundry "lump" used for the purpose.

If you look closely you can see characters (looks like them) in the bottom of those holes, that may refer to a particular set of die cast moulds to facilitate diagnosis in the eventuality of production problems further down the line.  Would allow them to withdraw casting sets and moulds from immediate production I guess, based on the line id incorporated.