Topic: Are all CB750 SOHC head gaskets interchangeable?

[Neuxstone]

I searched the archives and can't believe this subject has never been discussed or posted...
 Reading my Haynes Manual, there was a section that differentiated the year models and I read they updated the '75 CB750F0 motor with more dowel bushings between the head and cylinder...
 Does this mean there is a different head gasket for my 1975 F0?
 I'm totally rebuilding one I had in storage for years (frame up). I wanted to refresh the top end while it was out of the frame and am ready to order parts, which also begs the question; what is the best source for top end gaskets?
 Any other pertinent advice would be warmly welcomed...
Thanks ahead.
Dave

[WideAWAKE]

The answer to your question… are all cb750 sohc head gaskets the same… No.

What are all the differences and when do they occur in production, I don’t have an answer but there are many smart people here who I’m sure can rattle off that kind of info no problem.

[scunny]

There was a discussion on this topic the other day. I shall look for it.

[newday777]

The change came in the 77/78 F2 Supersport.
Your F0 uses the same as the 69-76 K models.

The 77/78 F has extra Orings and the head gasket has bigger holes where the extra Orings go for more oil flow.

[Don R]

 I'm thinking there are at least three types, early, late and F2/3.
 Not counting big bore sizes.  And don't forget the new head gaskets are thicker requiring either thicker O rings or milling the deck.   
http://www.cyclexchange.net/Tech%20Tips%20Gaskets.htm

[bryanj]

Early 750K,
Later 750K
750 F0/1
750 F2/3

There is a lot of crossover you need to check the part number for your specific engine then cross refer to what else it fits.

All bets are off if a po has been in thre and swopped parts

[HondaMan]

The K0/1/2 head gaskets were all the same. I call these the 'small stud hole' type.
Starting in the K3 the extra seals were added into the stud's holes, so the holes in the head gasket there got bigger (8 of them). I call these the 'large stud hole' type.
While the F2/3 engines show a different part number for the head gasket (-410- middle number), I have used the post-K3 gasket in those engines successfully.

If you have the 'large stud hole' type you may also use it in an early (K0/1/2) engine, although I add a 2x12 or 2x13 O-ring into each of the 8 stud holes to ensure they don't weep oil later. The Vesrah head gasket uses the 2x12, others (NE brand and "Made in Japan" generic brand) take the 2x13 size as their holes are slightly larger.

[Neuxstone]

Thanks.
 I should have elaborated that I have a "F0" 1975... I have conflicting info on whether it has the big holes for the 8 rubber stud sleeves.

[HondaMan]

Thanks.
 I should have elaborated that I have a "F0" 1975... I have conflicting info on whether it has the big holes for the 8 rubber stud sleeves.

It does have the bigger holes.

[Neuxstone]

OK Thx.
I understand all SOHC head gaskets have the larger holes to support either o-rings or rubber sleeves...?

[Don R]

 No, you can buy early (small hole) or late style (big hole) and in different bore sizes. Call CycleX or look on their web site.  If you look at the link I made above, there is a picture.

[HondaMan]

OK Thx.
I understand all SOHC head gaskets have the larger holes to support either o-rings or rubber sleeves...?

That's sort of a twisted description (not surprising it came from the internet?): if you get the wrong head gasket for the K0-K2 engines (one with the large holes) THEN you can use O-rings to seal the holes a little better. They are 2x12mm for Vesrah and 2x13mm for most others.