Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Wrenchpuller on August 17, 2026, 11:23:26 AM
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Hi all,
Quick question
When re-sealing the crankcase does the gasket goo only go around the outside or does it go on the outside of the bearing journals too, so oil doesnt go down the bolts?
It looks as if there was some on there previously, but i'm not sure if it would squash into the bearings.
Area in question circled in red
Thanks
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This question has come up before. IIRC the general consensus was to not put sealant by the crank bearings.
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How does the oil gallery look. Most of them are gouged by the primary chain.
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I have always put a thin smear there, same as all the way round to make sure of even clamping
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How does the oil gallery look. Most of them are gouged by the primary chain.
I havent seen any gouging from the primary, the guides look ok too.
I have always put a thin smear there, same as all the way round to make sure of even clamping
Yeah that was my thought with the thin smear for even clamping, but wasnt sure, especially if the consensus is to not bother
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Post a pic top down so we can see what it looks like. We may spot something you’ve missed.
I hope you’ve marked where the shells came from as they need to go back in the exact same place.
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Iirc my 400 showed remnants of the Hondabond on the center journal area, it was a pain to remove.
So I put some on that area when assembling the crank casings, I assumed it was done at the factory on assembly.
It is possible of course that a PO had split the engne casings in the past.
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If it's a 400/4 I have never seen any gouging in the primary chain / oil galley area (unlike the 500/550 where I know this is an issue). With 400/4 its usually the barrels and the upper area of the top crankcase that is gouged caused by the flapping of the cam chain where it hasn't tensioned properly as a result of owner incompetence or a broken tensioner bolt/gouged horseshoe. If your upper crankcase is gouged you'll see it, it will be a tramline in the tunnel of the barrel and the upper crankcase area of the tensioner will be worn to a point where the lower end of the tensioner blade sits.
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Just making sure I've got this right, the crankcase halves are the only place something like Hondabond is needed, and if you use good or genuine Honda gaskets everywhere else no bonding goo is needed?
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That is correct, genuine head gaskets have some sort of sticky seal around the cam chain tunnel ans oil passages
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Good point Dave. The pic looks like the bottom half of a 500, which made we wonder about the oil gallery. If however it is either a 350 or 400 then it’s not an issue as you say.
George, only on the crankcases, I tend to fit all genuine gaskets dry. Nothing on them at all. They come off easier that way as well. Honda tended to put a sort of glue or sticky patch where they consider it’s needed, like where the crankcases meet on a clutch case cover. I’ve reused loads of genuine gaskets, just use a craft knife to separate the gasket from where it sticks, don’t just pull the cover off, separate a small amount and run the knife around. Sometimes it sticks to the cover whilst somewhere else it sticks to the crankcase. I used to get them off intact about 90 times out of a 100. They never leaked afterwards either, so money saved.
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Thanks for that guys! ;)