Topic: cb750 combustion chamber size

[Mitchell]

Could someone tell me how many cc's the combustion chamber sizes are on a cb750 cylinder heads A/F/K? I have a k3 head and an A head and the A head has a slightly differant combustion chamber design I was just wanting to know the differance in cc's in the combustion chamber. Thanks

[gschuld]

K head should be between 22/23cc dead stock.  F head about 28cc stock.  Not sure about the head on the auto.

George

[TurboD]

The auto heads that I have checked are the same as the late K heads.

[Jerry Rxman Griffin aka MuthaF'er]

Auto heads, K7, K8, F0, F1 are all -392 heads so they should be equal to one another.

[cbr954]

I have had a stock late K head up at 24cc.  They very a fair amount but 22 to 24 is the normal range for the K heads that I have checked.  Have had a 1cc difference between chambers on the same head.

[HondaMan]

Could someone tell me how many cc's the combustion chamber sizes are on a cb750 cylinder heads A/F/K? I have a k3 head and an A head and the A head has a slightly differant combustion chamber design I was just wanting to know the differance in cc's in the combustion chamber. Thanks

The chamber on the "A" head is designed to boost midrange torque over the earlier "K" heads. It does it two ways" first, it stops some of the swirl-charge motion and second it provides a more hemi-shaped chamber. It seems to be about 22.8-23.0cc in volume, which would yield 9:1 compression with its lesser-duration cam.

[Mitchell]

Thanks guys just what I was wanting to know and I can see the more hemi shaped design on the A head compared to the earlier k head.

[Medyo Bastos]

the a, early f, and late k's actually have a lumpy and bumpy combustion chamber


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