Jeff K2
CB750 Member
I may be the last person in the world to know this, but in case anyone else does not, I have decoded the head numbers for SOHC 750s.
K - cannot find any number on the head, although the head was modified by RC eng.
F1 - 300_X - on the rear/upper/center fin
F2 - 410_X - on the rear/upper/center fin
I believe I have also figured out some of the head to cyl. compatibility;
You can put a K or F2 head on a F1 cyl., but you should pay close attention to the return oil flow galleys. Either seal them all or know where the oil will go.
NEVER put a F1 head on a K or F2 cyl., without providing O-ring seals at the outer oil return galleys AND adding oil return flow paths in the head for ALL of the outer valves.
F2 might work on a K cyl. as the valve galleys are joined. I may wrong as I do not have a F2 cyl to verify the return oil galleys.
Jeff K2
K - cannot find any number on the head, although the head was modified by RC eng.
F1 - 300_X - on the rear/upper/center fin
F2 - 410_X - on the rear/upper/center fin
I believe I have also figured out some of the head to cyl. compatibility;
You can put a K or F2 head on a F1 cyl., but you should pay close attention to the return oil flow galleys. Either seal them all or know where the oil will go.
NEVER put a F1 head on a K or F2 cyl., without providing O-ring seals at the outer oil return galleys AND adding oil return flow paths in the head for ALL of the outer valves.
F2 might work on a K cyl. as the valve galleys are joined. I may wrong as I do not have a F2 cyl to verify the return oil galleys.
Jeff K2