Author Topic: 500/550 head gasket O rings  (Read 832 times)

Offline Bryanj

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500/550 head gasket O rings
« on: May 23, 2025, 02:47:17 AM »
As reported the 500/550 can leak at the head gasket oil feed O rings due to modern asbestos free gaskets being thicker.
Having talked to Mark Paris (Hondaman) on the US site i have ordered a quantity of the bigger size to get the price down to 15p each so if any body wants some pm me and i will work it out.

The permanent fix is to mill about 5 thou off the rop of the block but works out considerably more expensive.

Regards to all

Bryan

Offline Oddjob

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Re: 500/550 head gasket O rings
« Reply #1 on: May 23, 2025, 01:33:31 PM »
Or fit genuine head gaskets OR fit a copper head gasket the correct thickness and never have to buy a head gasket again.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Bryanj

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Re: 500/550 head gasket O rings
« Reply #2 on: May 23, 2025, 04:56:39 PM »
I fitted a genuine one and its still thicker and leaks

Offline Oddjob

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Re: 500/550 head gasket O rings
« Reply #3 on: May 23, 2025, 08:33:57 PM »
They didn’t leak before with a genuine so why would it leak after?

I have a few NOS gasket kits lying around, quite a few bottom end ones as well.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Bryanj

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Re: 500/550 head gasket O rings
« Reply #4 on: May 23, 2025, 08:37:07 PM »
Because Honda took the asbestos out as well as they had to and they are now thicker, i used a genuine nos top set last year on a rebuild and its weeping

Offline Oddjob

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Re: 500/550 head gasket O rings
« Reply #5 on: May 23, 2025, 09:32:32 PM »
Got to say Bryan I’ve never had a leak with a genuine gasket set, have with stuff like Vesrah etc
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Bryanj

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Re: 500/550 head gasket O rings
« Reply #6 on: May 23, 2025, 10:47:46 PM »
Neither had i till this one, now going to fit the bigger O rings anyway

Offline Oddjob

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Re: 500/550 head gasket O rings
« Reply #7 on: May 24, 2025, 01:09:53 PM »
I've considered this for a good time Bryan after seeing Marks posts on the matter. What concerned me was the calculation of the ideal size. You are limited to the diameter by the recess it sits in, if you increase the thickness would that mean if you got the amount wrong the internal hole might close up as the ring got crushed, it can't go outward as the recess stops it, so it would be forced inwards and thus possibly restrict the oil flow to the head.

Valid point or did I overthink it?
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Bryanj

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Re: 500/550 head gasket O rings
« Reply #8 on: May 24, 2025, 01:34:02 PM »
It is Valid Ken but having talked at length with Mark i am 95% that its ok, will check oil flow though.
I would prefer to take about 3 thou off the block but finding somebody to do it and the cost is the problem.
Keep it safe

Offline DomP

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Re: 500/550 head gasket O rings
« Reply #9 on: May 24, 2025, 05:34:38 PM »
I did Bryan's other method, skimmed head when I fitted new liners.  No weeps here, not that I've gone very far on it
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline Bryanj

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Re: 500/550 head gasket O rings
« Reply #10 on: May 25, 2025, 12:23:05 AM »
I remember those liners!!

Offline DomP

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Re: 500/550 head gasket O rings
« Reply #11 on: May 25, 2025, 07:32:37 AM »
Yeah they were a bit of a headache but all good now
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

 

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