Topic: 78 750F vs 76 750F Carb/Head Difference?

[raymond10078]

I see in the parts microfiche that the 76 carb rubbers have different part numbers than the 78 carb rubbers.  I also see that the 76 and 78 heads differ,  but I was under the impression that the on-head carb connections (spigots?) spacing and size were the same.  So, I'm concluding that the carbs themselves must differ.  So my question is - what is the difference, carbs, heads, or both?

These might seem like odd questions - and here's the real question behind these two questions:

I have a CB750A.  The head for this bike is the same (same Honda number) as the 76 750F head.  Therefore, I'm thinking that I can swap out my cam for a good mid-range cam, and also swap out my carbs for a 77/78 set, and use 77/78 carb rubbers.

I realize that the non auto carbs won't have the "in gear" off-idle dashpot, but I am not worried about that (right now).  What I should end up with is a marked improvement, although the compression ratio will still be lower than the comparable 76 750F bike (due to the 750A pistons).

Any/all info would be appreciated.  I don't have access to the various years of parts to check this out physically - maybe someone knows, or has parts that could help answer these questions . . . .

[SOHC Digger]

I do know that the 77-78 carbs can be mounted on earlier engines and vice-versa, but the rubbers must match the carbs.  My first 77K came with earlier carbs and rubbers and ran great.

Lots of people convert carbs for various reasons.  Some want the accelerator pump of the PD's, etc.  It can be done, it's up to you to tune them, though.

[strawhouse]

I was told that I could switch out the carbs from my 76F and put them on my 78F.  The guy that told me this said he had done it before.  All word of mouth