Finally got around to tearing down my xs650 (1977) and found something I have never seen in other bikes. In the surface of the cylinder there is a channel machined into it which runs around both cylinders and a matching channel in the surface of the bottom of the head. Does anyone know why its there? The head gasket will separate the 2 channels so I can't see any use for it.
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Oil slot on top of cylinder?
- Thread starter cb550
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- cyl channel
Welcome to the forum, cb550.
That "groove" thing started in 1972.
Justa 'nuther oldschool trick to prevent head gasket leaks...
That "groove" thing started in 1972.
Justa 'nuther oldschool trick to prevent head gasket leaks...
bikefreakjon
XS650 Addict
Don't use gasket sealer on the head gasket
OK I am not doubting your word, but I have always heard not to use gasket sealer on head gaskets but I have always used copper gasket sealer (spray on) on head gaskets, especially on the bikes like the xs which seem to be prone to head gasket leaks. What is wrong with using sealer on the head gasket?
bikefreakjon
XS650 Addict
1: makes a mess, almost impossible to get a thin enough layer.
2: the next person to tear down the engine will hate you and curse you for a hack.
3: the factory has all manner of glue at their disposal (see cam cover/head interface) and they didn't need glue.
As a rule, I only use sealer/glue if a mating surface is bunged up or as an external temporary repair. There is nothing to be gained by trying to upgrade or reinforce a good gasket when you have clean smooth flat mating surfaces.
If it came from the factory dry, leave it dry.
Just think what a bb sized blob of sealer can do in an oil passage!!!
2: the next person to tear down the engine will hate you and curse you for a hack.
3: the factory has all manner of glue at their disposal (see cam cover/head interface) and they didn't need glue.
As a rule, I only use sealer/glue if a mating surface is bunged up or as an external temporary repair. There is nothing to be gained by trying to upgrade or reinforce a good gasket when you have clean smooth flat mating surfaces.
If it came from the factory dry, leave it dry.
Just think what a bb sized blob of sealer can do in an oil passage!!!
Steve C
XS650 Addict
So, spray on copper coat gasket sealant is recommended by several members here and is called out by name in the venerable top end build up thread in the tech section. I think it's a good product to ensure that an air cooled motor's head gasket makes a good seal. Stay away from any goo's from a tube tho except where needed (case halves, rocker cover) and use the right stuff; yamabond, 1104, aviation sealant NOT multicolored RTV! I like to coat gaskets in engine oil so I have a fighting chance at removing them or the possible option of reusing where appropriate.
Good luck!
What motor oil do you use on your gaskets? 
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Use the copper spray on the head gasket.
If you do it like I suggested in the top end thread, it doesn't make a mess.
I don't care if someone calls me a hack.
The factory ain't the "be all to end all."
The main purpose of the copper head gasket spray is the aid in heat transfer from the head down to the cylinders. When it comes to air cooled engines, I'll take every little cooling advantage I can get.
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The thin ledge twixt the cylinder and the tunnel is a known troublemaker. even on the "way back machine" some sticky was advised along there. Don' get me started on that long thin edge above the cam chain tensioner held by ONE stink'n 6mm bolt into short aluminum threads.
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Steve C
XS650 Addict
Well now. Glad you asked, unless your using genuine Penn State Quaker Lube Blenz-Well...0w-50 mind you...Whzt motor oil do you use on your gaskets?
You ain’t shit!
Well I am glad to get such a lot of opinions about this. First of all I NEVER use any kind of silicone sealer anywhere on my bikes. Unfortunately I have personal experience with what it can do if it gets into an oil orifice! I always use Yamabond 4 or equivalent every where except the head and base gaskets where I use the Coppercoat spray and have never had a problem with that combination of products.
bikefreakjon
XS650 Addict
I see, well then you are good to go!
