Hi all, this is my 1st post. Hopefully nothing too controversial.

From Pete Shoemark's book HONDA CB750 of 1983, (allowing many things have changed since then, and new information is broadly available, and reference terms change), he has a chapter that talks of the evolution of the CB750 thru to the K8.  

Anyways, allowing that K0 has become the name used for the model following the Sandcast, the Bonhams bike may seem out of place.   But back in the day K0 wasn't the model description, as I recall folks used to use the term pre K after the K1's arrived, again different time different terms (and K0 is simpler than pre K).

Back to the book, and allowing the 1st bikes including Sandcast are just referred to as CB750's, the book suggests the following and I quote;

" The KO was a transition model, generally similar to the CB750 and grouped within the latter's batch of engine and frame number span.  The K0 variants will fall between Engine no CB750E 1044848 - 1045147, Frame No CB750 1044826 - 1044947. all other details, paint colours and plating are as given above (refers to CB750 in the book). Only 36 K0 machines were sold in the UK.  In most respects, the K0 bore a very close resemblance to the CB750, but featured rocker arm and linkage type carburettor bank in place of the cable operated system. This later system was continued through the K series".

Using the Pete Shoemark book as a reference point, suggests the Bonhams bike is in fact a unique model of its own, whether (past or current) use of the term K0 is correct is another matter.

Cheers Pete (no connection to Mr Shoemark)