Topic: CB 750 cylinder head - sorry...

[Sgt.Pinback]

.. to ask again.

Can you please identify those two heads (top/bottom) ?

[Sgt.Pinback]

Any ideas?

Which one is older

[kmb69]

The top head is the older casting.

[MCRider]

The top head is the older casting.

Keerect. (Just as confirmation)  The Oring cutouts, around the stud holes is the absolute giveaway, to me anyway. Orings were used in the later heads, not the early heads.

[754]

The halfmoons near intake on gasket surface,  I Believe are  77/78 heads..the other looks 73-76

[MCRider]

The halfmoons near intake on gasket surface,  I Believe are  77/78 heads..the other looks 73-76

The top head has to be earlier than K3-K4 cuz that's when they started using the ORings around the cylinder studs of the return oil passages.

[754]

That style of head first appeared in the K3 run near the beginning, look at top front fin. From the side will have 3 oval bars between fins. First K3...some still had K2 heads.

[MCRider]

That style of head first appeared in the K3 run near the beginning, look at top front fin. From the side will have 3 oval bars between fins. First K3...some still had K2 heads.

I was guessing about the K4. Not quite sure when the change was made, thanks.

[Sgt.Pinback]

I live in Germany...... No K3,K4 here.

 

[754]

1970 = KO
1978 = K8...........over here..,
 but after say month 7 or 8 of say 1973, it would be the next year model..in this case K4