CB750 Gasket sets - any recommendations

[Zunspec]

Hello,

I intend to lift the head on my 750F1 engine to re-lap the valves to address a small issue with low compression readings.  Is there a favoured brand (apart from Honda OE) for a top end gasket kit.  I do not have adequate knowledge to order all the gaskets, O-rings etc. individually.

Cheers  Geoff

[MrDavo]

I've recently bought an Athena set, after reading good reviews, and while I'm not in a position to use it yet, it seems good quality, and includes stuff like the rubber seals that go in the cylinder head, and a load of O rings. I guess only when I can build the motor I'll find what's missing.

Ash says that the NP sets are very good, but the only CB750 set I could find turned out to be incomplete, as the 'borrowers' had been at in while it was in stock.

The ebay listing I bought from shows what you are going to get, unlike most ads that show a set in its packaging.

http://www.ebay.co.uk/itm/For-Honda-CB-750-K-Four-1972-1975-Athena-Complete-Gasket-Kit/302093894735

[Zunspec]

Thanks MrDavo,

That looks a pretty comprehensive set.

Cheers  Geoff

[royhall]

Dont be tempted by the price of the Cruzinimage set. Last one I had for the 750 was rubbish.

[Zunspec]

Hello Roy,

The CruzinImage products do seem to be bit hit-or-miss.  Some of their kit is good, others.....questionable.  I like the offering from Cycle-X but their shipping is more than the price of the gasket kit.  I'm not in a rush, the top end re-fresh will be a winter project.

Cheers

[royhall]

Your right about Cruzinimage being hit and miss. I should have said the kit I had off them for the CB350F was very good. Just the 750 kit that was rubbish, and others have said the same.

[Trigger]

I always use original head gasket and Vesrah for the rest. Though Vesrah do not include the pucks anymore on the 750K's anymore.

[Zunspec]

Thanks Trigger,

During my searches on the subject several times I have seen the "use genuine Honda headgaskets", I'll do the same. Although I can remove the top end whilst the engine is still in the frame on the Seeley so not so much work compared to having to remove the engine to replace a head gasket.

I'm still trying to work out what function these "pucks" perform but obviously they are needed.

Cheers  Geoff

[Bryanj]

They seal up the holes you need to get a socket in to torque the head

[Zunspec]

Thanks Bryan, More knowledge gained.

[AshimotoK0]

Interesting discussion from the 750 Sandcastonly site. Personally I am just going to use the NP one I have with the extra 'O' rings detailed in the Service Bulletin. The NP gasket set BTW is the only one I have found with the rubbers for inbetween the cylinder fins included in the gasket set (not sure on Honda one ...so long since I have seen one). The pucks are used to seal the holes that give access to the recessed  head nuts.

Don R
Head gasket Q?
« on: November 02, 2016, 01:01:30 PM »
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 Is there a source for proper head gaskets for an early head? If I were to contact cometic about making some I'd assume I need the thickness and composition information. Not having one for comparison I wonder how close the rest of the gasket is besides the center bolt?
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Re: head gasket Q?
« Reply #1 on: November 02, 2016, 03:19:19 PM »
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Other than the extra hole at the front the other bolt holes are smaller in diameter. The newer gaskets also have a sticky area between cylinders 2 and 3 to help with sealing which was a good feature.The early production gaskets didn't have this. I'm sure you would get a lot of interest if these were remanufactured
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Re: head gasket Q?
« Reply #2 on: November 03, 2016, 10:21:16 PM »
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the sticky head gaskets make head removal a horror.  the issue of preventing oil leaks is as much in the thickness of the head gasket
 as it is in the thickness of the O-rings fitted.  I've started using Vesrah head gaskets and a slightly thicker O-ring and had no oil leaks running the engine on the test stand and during operation in the frame.  i don't have the thicker O-ring measurements as i write this, I  do have the measurements at my shop.

Steve Swan

[philward]

Ash
Do you have the size of the extra thickness o rings that is referred to in the quoted post above. I remember fitting them to my last rebuild but didn't keep the info - It will same me trawling .net again if you have the size
Thanks
Phil

[AshimotoK0]

From memory it was something like 15 mm i.d. x 1.5 dia. in Viton   but that's purely from memory of a very old email sent to me. I have emailed the restorer who originally gave me the info and I will get back to you Phil

[Trigger]

From memory it was something like 15 mm i.d. x 1.5 dia. in Viton   but that's purely from memory of a very old email sent to me. I have emailed the restorer who originally gave me the info and I will get back to you Phil

It will all depend on the thickness of the gasket, the ID of the stud hole in the gasket and what 750 engine it is for

[philward]

My 'recent topics' screen has disappeared! Is it just my PC or is it the same for everyone?