Honda-SOHC
Other Stuff => Misc / Open => Topic started by: Seabeowner on August 31, 2025, 04:06:42 PM
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Looking to buy some sealant for crankcases and the like and when you search Hondabond a variety of sealants turn up.
Had some Threebond 1215 (I think) some time ago and that did a good job. Have some Threebond 1104 (rubber based), but that's gone off. I see Hondabond HT is silicone rubber based and thought I was supposed to steer clear of that.
Is Wellseal any good? What about Yamabond 4 or 5?
Thanks
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Looking to buy some sealant for crankcases and the like and when you search Hondabond a variety of sealants turn up.
Had some Threebond 1215 (I think) some time ago and that did a good job. Have some Threebond 1104 (rubber based), but that's gone off. I see Hondabond HT is silicone rubber based and thought I was supposed to steer clear of that.
Is Wellseal any good? What about Yamabond 4 or 5?
And I really want it grey.
Thanks
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Looking to buy some sealant for crankcases and the like and when you search Hondabond a variety of sealants turn up.
Had some Threebond 1215 (I think) some time ago and that did a good job. Have some Threebond 1104 (rubber based), but that's gone off. I see Hondabond HT is silicone rubber based and thought I was supposed to steer clear of that.
Is Wellseal any good? What about Yamabond 4 or 5?
Thanks
Discussing crankcase sealant is probably a bit like discussing engine oil or tyres I suppose, everyone has their own preferences.
But during the seventies in the trade we always sparingly applied Blue Hylomar to spotlessly clean crankcase joints and cleaned off the surplus with a petrol rag when assembled and set.
It worked then and still seems to work now, for me at least.
Good luck
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I used Hondabond as recommended by NJ I think.
It needs to be a really thin layer of sealant, wearing surgical type rubber gloves makes this easier, you don't want excess sealant entering the inside of the engine
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Dont know about new wellseal but the stuff in the 70's set hard like a shellack so would not recommend it.
Hylomar we used to use BUT THINLY, yamabond and hondabond should be similar and ok
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I still use hylomar always found it works fine.
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I use Wellseal on the Triton because lets face it its British and no matter how hard you try it is nigh on impossible to seal the joints from leaking. I find Wellseal if used properly on each mating face and either side of a paper gasket (or copper gasket in the rocker box) stops any leaks.
I wouldn't use Wellseal on my Honda's though but then I've never had a problem with Honda's leaking oil.
The CB250RSA had paper gaskets with a thin bead of what appeared to be dried silicon applied during manufacture to form an oil tight seal.
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Is it only with genuine honda gaskets that you don't need sealant?
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I have use both Hylomar and Hondabond with equal success. Wellseal on the old Matchless. Never had to use sealant with gaskets.
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Sealant on Honda gaskets is not required, in fact it will make them almost impossible to remove cleanly if you ever need to remove them. Honda put a film of adhesive on the areas where leaks could occur, like where the crankcases join on the clutch gasket and around the cylinders on the head gasket. Without any sealant you can often remove the gasket without breaking it and reuse it, something I used to often do when servicing the 250N and had to remove the clutch casing to get to the balance chain.
Thin smear of Hondabond or similar only on non gasket areas like the crankcases is all that’s required.
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Thanks for all that. And as was said it's a bit like starting an oil thread. I notice no one mentioned Threebond which comes up everywhere when you search Hondabond.
And there seem to be different Hondabonds (HT which I think is black and Threebond 1207B is sold as the same stuff and 4 (which I can't find in the UK any more) and Yamabonds (4 & 5)
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Would like to get Hondabond 4 but doesn't seem to be available in UK so minded to go for Threebond 1184.
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Would like to get Hondabond 4 but doesn't seem to be available in UK so minded to go for Threebond 1184.
https://www.coxmotorparts.co.uk/honda-oils-fluids/genuine-honda-hondabond-ht-liquid-gasket-1-9-fl-oz/?gad_source=1&gad_campaignid=19274274716&gbraid=0AAAAADr3dvjnN-IGAtcjAkgtoI6U8aUHl&gclid=Cj0KCQjwzt_FBhCEARIsAJGFWVnvQmR-v0kRvc7H15C1JkHi3W9lqrSr8j3uqUSwvFXrDx7iIYQZs8oaAjUYEALw_wcB
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James,as I understand it HT is not the same as HB 4 and also think it's black.
HB 4 widely available in the US and found one site in Europe. There has always been a Threebond equivalent and think that 1184 is it.
Phil