Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: neat street on May 04, 2024, 10:03:39 AM
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Hi All
not been on for a while, now have a CB500 1973 to go with the 750, and taking top end down. could anyone please recomend a top end gasket set? (hopefully complete) :-)
thank you
John
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I can't
But most do not contain the rubber pucks,
Also the valve stem seals can be a bit iffy
Might be worth buying those separately
Sent from my SM-A546E using Tapatalk
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thanks John, :-)
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No matter what set you need thicker O rings at the headgasket than those in the set
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No matter what set you need thicker O rings at the headgasket than those in the set
Does this apply to all gasket sets Bryan or just relating to this particular model? I will be putting the top end back together on my CB550 in the next month or 2 and it would be good know if I’m going to need to source some different O rings.
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All head gaskets are now thicker than Honda original due to no asbestos used in manufacture but the suppliers still give you the original size O rings so they dont seal as well.
If you go to the US site and look up Mark Paris (Hondaman) he can sdvise on size, i dont have all my books to hand
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Thanks Brian, good to know and will have saved some headaches later. :-)
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Maybe get the block skimmed which will make the oring recess slightly shallower, that's what I did following Brian's advice after he rebored my block. I used Vesrah gaskets from DS
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I have a local source for most O rings
A company called Hayley Group
On a local industrial estate, the Hereford branch are really helpful,
Imperial, metric,fuel resistant etc,
And the bonus, normally a fraction of the cost of NOS,
Take a sample, and the item, like tappet cap ,they will find the size needed
Sent from my SM-A546E using Tapatalk
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It depends which gasket set you use as to the size O rings you will need. All the kits have different depth head gaskets.
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I have a local source for most O rings
A company called Hayley Group
On a local industrial estate, the Hereford branch are really helpful,
Imperial, metric,fuel resistant etc,
And the bonus, normally a fraction of the cost of NOS,
Take a sample, and the item, like tappet cap ,they will find the size needed
Sent from my SM-A546E using Tapatalk
Now you tell me John!😄
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I have a local source for most O rings
A company called Hayley Group
On a local industrial estate, the Hereford branch are really helpful,
Imperial, metric,fuel resistant etc,
And the bonus, normally a fraction of the cost of NOS,
Take a sample, and the item, like tappet cap ,they will find the size needed
Sent from my SM-A546E using Tapatalk
Thank you John
Great tip and advise :-)
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It depends which gasket set you use as to the size O rings you will need. All the kits have different depth head gaskets.
Thank you nurse Julie
any adea on the difference I should be looking for from gasket thicknes to `O ring`? or how would you work out what size would be best to use?
thank you again
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Check the thickness of new gasket compared with old and the difference then added to standard o ring thickness.
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thank you Johnny, the old gasket is completely damaged beyond measurement, had to scrap off, but thank you for the tip
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This might help you a bit. I fitted the the 2.5 mm thick 90 hardness rings after reading this and they've been fine
https://www.sohc.co.uk/index.php/topic,28673.0.html
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Thank you Dave, this has helped alot :-)
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I went through a nightmare around DS aftermarket gasket set tring to fix an oil leak.
I ended up using the aftermarket O rings along with a proper Honda OEM gasket plus having head skimmed.
As many have said the relative thickness of head gasket and O rings is critical to getting a oil tight seal.
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Its not the head you need to skim but the barrel so as to reduce the depth of the recess for O ring by 3 to 5 thou.
I did once think aboutputting a small shim in the recess but getting an accurate sized shim that thin did not appear easy
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I always used a light film of GE Silicone (pure Silcone caulk, not the paintable goop) on the head gasket and the O-rings for the oil passage. It was a poor design relying on the O-ring alone between the head and the cylinders. Why they didn't have a similar setup for the cylinder to crank case with the oil jet is a mystery. However I've got Yoshimura big bore kits with higher compression pistons in both my CB500's and they never leak at the cylinders or the oil passage. You have about a half hour before it starts to set too much so make sure you get the head on and torqued within that period. The silicone also makes for an easier cleanup the next time you change the gasket. Paint thinner or mineral spirits seems to slowly eat the film left behind.
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Not a favourite of silicone, just a tad tpp much can block the oilways. When using original Honda top sets we never had a problem till asbestos was removed from the fibre material
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thank you all for your help, really appreciate your comments
thank you