Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: UK Pete on April 09, 2010, 06:03:57 PM
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I am about to rebuild my engine, i have all the parts i need, and have sprayed all the engine cases up so its all ready to go, my question is does any one hear who rebuilds engines or has rebuilt the honda 750 engine in the past use any gasket cement in addition to the gaskets or just use the gaskets dry.
The reason i ask is that in the past on other old jap engines i have built , i have found the need to use a very thin smear to the casings to take up some of the uneven or slightly scratched surfaces.
I have used THREE BOND LIQUID GASKET 1104 on my crank cases but wondered if a thin smear of this or something else in addition to the gasket would be of benifit. also the cylinder head surface is far from perfect is there anything i should use there i really do not want to take it out the frame and all apart again once its done.
pete
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I never used anything on gasket faces, maybe a little grease to hold the gasket in place but that's it, when putting crankcases back together I used a smear of Golden Hermatite, and I do mean a smear as the oilways for the top end are very small and easy to block up, so being a bit sloppy with gasket goo can be very expensive.
Cheers
Den
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I always used grease on the head and base gaskets. They just seemed a bit "dry" without anything.
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It's grease all the way for me.
Silicon Bathroom sealant (clear) for crankcases is the way to go. I've used it on my Matchless and it's continent full stop.
trust me I've minutes of experience !!!! ;D
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Hylomar blue on the crankcase halves & the pucks under the cam towers ;), grease on all the other gaskets plenty of oil when your building up helps to :), cheers Mick.
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Just remember Silicone doesnt like petrol , so I would stick with the Three Bond , its designed for 2 stroke crankcases where leaks = no power ,
I've allways used a thin smear of gasket cement on gaskets, and Red Hermetite for anything petrol related.
Just taken apart my Suzi GT250 crankcases which the previous builder had used blue silicone on hed also rebuilt it with a rough main bearing , now that was really going to work !
Simon 750K3 Suzuki GT550L Suzuki GT250B
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Also
If your building it and leaving it for a few months try using Graphogen on the cylinders and other surfaces that might rust.
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Hylomar blue on the crankcase halves & the pucks under the cam towers ;), grease on all the other gaskets plenty of oil when your building up helps to :), cheers Mick.
I like to use Blue Hylomar on base gaskets around the oil ways, making sure that there are new 'O' rings around the cylinder sleeves where they protrude down into the top of the top crankcase.
The 'pucks' under the cam carriers is another good place to use Blue Hylomar.
On the OEM 750F2 head gasket there is a coating around the cam chain tunnel which should melt & seal this area, but if as Peter says there are a few 'imperfections' in the gasket mating surfaces I always use what Pops Yoshimura recommended, which was/is a thin smear of copaslip on the head gasket. Since learning of this trick i've done this on all graphite head gaskets, be they car or bike, & never had another gasket let go.