Author Topic: 1978 CB 750 F2 - Oil pouring from above head gasket  (Read 589 times)

Offline SteveD CB500K0

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Re: 1978 CB 750 F2 - Oil pouring from above head gasket
« Reply #15 on: May 10, 2020, 08:46:24 AM »
Anyone care to explain what an MLS gasket is for those of us who haven’t a clue?


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Offline Trigger

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Re: 1978 CB 750 F2 - Oil pouring from above head gasket
« Reply #16 on: May 10, 2020, 09:04:51 AM »
Anyone care to explain what an MLS gasket is for those of us who haven’t a clue?


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Multi layer is a number of steel plated gasket with a sealer between the plates. Some have rivets to keep the plates together and are not suitable for some heads unless, you start machining recesses out for the rivets to sit in.

Offline Trigger

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Re: 1978 CB 750 F2 - Oil pouring from above head gasket
« Reply #17 on: May 10, 2020, 09:27:41 AM »
I used HT Howard in Slough who use equipment that detects the metal type and adjusts the cut accordingly; in this case it accounted for the alloy head and steel liners without the need to remove the liners and the associated work you mention. The cut is excellent.

The original oval fire-ring gasket for the F2 is obsolete from Honda; do Vesrah make the oval type? Anyhow, the cost of the skim was reasonable and with the reduced leak potential promised by the MLS gasket I thought it a good idea, but time will tell.

Thanks for the information.

Honda 410 head gaskets are ready available  ;)

Offline stoutgoose

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Re: 1978 CB 750 F2 - Oil pouring from above head gasket
« Reply #18 on: May 19, 2020, 09:00:13 AM »
Update to close the thread. I removed the engine and stripped the valve gear to take a look at the studs. I located the copper sealing washers which weren't in the correct place (my manual made no mention of sealing washers and cap nuts). I removed the Kibblewhite nuts on studs 5-8, annealed the sealing washers and put them on studs 5-8 along with the correct cap nuts, and reassembled the bike.

Problem solved. The engine is now leak-free. It is rather surprising just how much oil can find its way down a stud thread and under a standard steel washer.

I'm now off to burn my 'Honda' manual and the Haynes version, and locate a real one. Many thanks for all your replies.


Offline K2-K6

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Re: 1978 CB 750 F2 - Oil pouring from above head gasket
« Reply #19 on: May 19, 2020, 09:31:51 AM »
Good news you've sorted the problem.

The Honda manual I posted picture from (it's not mine but belongs to an F2 owner) has a part # 6141000

Just searched with "Honda 6141000" and quite a few come up for sale. It is their genuine manual for the last of sohc 750 it seems, pretty comprehensive for specs etc too.

Offline SumpMagnet

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Re: 1978 CB 750 F2 - Oil pouring from above head gasket
« Reply #20 on: May 19, 2020, 05:10:56 PM »
I found a PDF copy of that manual on the net a while back.....it's a handy document to have.... took a while to print off too
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Offline stoutgoose

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Re: 1978 CB 750 F2 - Oil pouring from above head gasket
« Reply #21 on: May 22, 2020, 08:56:17 PM »
Many thanks.

 

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