Head gasket question

[rasputin]

I have an Athena full gasket set here that I just checked because this thread made me curious. I get 74.00 mm on each cylinder.

[Jonesy]

I was lucky enough that when I bought each bike, the PO's had some extras that included an after market gasket kit. I used a fair few of the gaskets on the 581 rebuild and what I have left is the remains of a "VERSAH" branded kit from Japan and a "CENTAURO" kit from Italy, I used a genuine head gasket on 581 and gave one to Brett and I'm not sure which kit the remaining one that I measured is from. Both Kits say that the head gasket replaces 2H7-11181-02-00......maybe the UK part finder link has info on O/size gaskets?

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EDIT
A short time later.....had a look at the UK part finder and it quotes the holes for a genuine to be 72.5mm
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EDIT 2
A little bit more laterer
Maybe the after market dudes pre-empted purchasers of the product were going to O/size or big bore kits....just think'n

[Eveready1100]

Paul, what brand is your kit?

[steptoe]

seems like we might be onto something,,,, what size kit did you think you were buying

[Jonesy]

Just for the records, I've got a gasket here out of an aftermarket kit that measures 74.1mm.

[Fred]

Like you Errol, (before this thread), I would have ordered a big bore head gasket without checking the one in my spare kit first as I knew it to be for a standard bore application.

Lucky its only money eh

[wacko-ocker]

here is a tech tip for you everyready  focus the photo before you press the button

[Eveready1100]

Just curious, Fred. Would you have measured your head gasket that's in your kit first, or just ordered a big bore one from Wiseco?
Prior to this discovery, that's just what I would've done.

Here's the other bore sizes for anyone contemplating buying a gasket set -
The stock bore is 71.5mm, the 1179 kit is 74.00mm, and the 1196 is 74.5mm

If anyone can get their mitts on any other branded gasket sets and do a bit of measuring, post them up here for future reference so members can maybe shop for a specific brand that will fit their motor properly.

So it looks like 516 will be receiving Bryan's head gasket to fit its 1179 pistons.

[makzy]

To answer the question of head gasket size, so long as it does not intrude  into the combustion chamber at all it will be ok, 1.5mm outside the cylinder is about as good as you could get, more is still ok, what you will get with a gasket protruding into the combustion chamber is a very hot edge of the gasket which will cause pre-ignition and early gasket deteriation . cheers. 

[steptoe]

while Ev was here on the w/end we actually discussed the possible dire outcomes,,

a suggested name for the thread was going to be who,s wasting money,,

going on the fact that the positioning of the gasket is approximate, giving the amount it can move on the locating dowels when reassembling,, it,s possible it can move whilst placing the head on, and the amount of distance the folded edge comes over the gasket paper and the fact the piston doesn,t come past the gasket, will it make a huge difference if the gasket is hanging over the lip of the bore either by being over/under size by a poofteenth or by moving over the lip of the bore by moving whilst refitting the head

a std bore is obviously 71.5mm, 2nd over is 72,, all the larger lip would do is give a tiniest bit larger combustion chamber which obviously can be handled by the gasket. 

maybe it,s a marketing ploy to get a few more dollars out of the uninformed buying motorcycling public
by telling us we need to buy oversize gaskets specifically and there are no dire outcomes

[Fred]

An interesting thread this  with possible dire consequences

My standby full gasket set is a "Vesrah" made in Japan for standard bore application and the Head Gasket comes in at an exact 75.00mm

Now, I've actually got a Wisco 1179 Kit in mine which by my uptake of this means that my spare Head Gasket will (by default) actually fit my bore?

Comments???

[Eveready1100]

Lou, that coffee was freshly made!
Regarding the "cheap" gasket set, here's the link - CLICK

Currently running at AU$58.80 with $13.00 postage

[beemeerr11]

Coffee looks like it's going cold

The cheapy gaket set , is it local or imported only asking for future reference as I see kits like these in various countries on SleeZ-Bay?

Cheers

Lou

[Eveready1100]

Haven't had any first hand experience with XS11's as yet, though with my other past multi's that I've done up, oversize head gaskets had to be sourced separately. Mind you, BK are a pretty switched on mob, so they may well have supplied you with a "custom" gasket set.

[AussiXS11G]

my donation came from BK spares ....I may have tod him I would be boring the unit...do the sets come as oversizes?