Cometic gaskets are now metal laminated

I just bought a Cometic brand gasket set for a 102.4mm bore. Surprisingly, the head gasket is a laminated three layer metal gasket that looks very similar to Honda OEM.

And, the base gasket is single layer metal that I measured as 0.018" thick.

for what bike? xrl I supoose? interesting

I just installed a cometic head gasket, well 6 months ago or so...it had metal in it but had that grey fiber glued to it...in any case OEM is always best

thats interesting about the base gasket...

mine is cometic too...but it was a rubbery gasket, not metal

I wish I had a thin metal one to up my compression a bit, jajaja

The gasket set was labelled as for an XRL. The head gasket looks so similar to OEM that I wonder if Cometic is just rebadging gaskets from whoever makes them for Honda.

I'm also thinking about a thin base gasket to slightly increase compression. I may use the metal base gasket as a stencil for making a new base gasket out of some 0.010 material. I've heard of people using only RTV in place of a base gasket. RTV can seal crankcase halves on a two stroke to be air tight.

Although changing gasket thickness does alter the cam timing slightly.

since I have an hrc cam replica I wonder if that would be better or worse with the altered cam timing(retarded right) I think it would compound it more and nee to be moved a tooth forward...no?

The gasket set was labelled as for an XRL. The head gasket looks so similar to OEM that I wonder if Cometic is just rebadging gaskets from whoever makes them for Honda.

I'm also thinking about a thin base gasket to slightly increase compression. I may use the metal base gasket as a stencil for making a new base gasket out of some 0.010 material. I've heard of people using only RTV in place of a base gasket. RTV can seal crankcase halves on a two stroke to be air tight.

Although changing gasket thickness does alter the cam timing slightly.

I want to try to make one out of copper...but using a dry type of sealant like spray...that rtv or similar get REALLY thick sometimes...defeats the purpose in a way

anybdody do this succesfully...

Thinner gaskets would create more slack in the timing chain, moving the cam in the same direction as a worn/ stretched chain. I think it retards the timing.

For copper gaskets, there's an aerosol spray that's finely ground copper particles in a sticky adhesive.

This is a C&P from the KLR site about Cometic viton covered metal base gasket for the KLR. Whether or not these gaskets will weep on XR's , who knows. But their definitely having a problem with them on the KLR's.

Question

Well it has been 300 miles for the break in and doing a oil change I notice a slight misting around the cam chain tunnel at the gearbox. I used #2Mr Gasket , I did not get heavy with it I applied a fairly even thin layer on both the head and the gearbox. What went wrong with this?

Yep I torqued it down, that front hidden bolt. If I pull the head and go back and re-torque the it, what are the odds it well stop seeping?

Do I order a new gasket and redo it?

It's a 685 kit.

Answer

i am assuming you used the Cometic .010" or .020" supplied viton covered metal base gasket....if so, they DO weep...i stopped using them well over 100 685/688/705 kits ago as did EagleMike....

i now recommend the OEM .020" fiber base gasket coated with Loctite 515 anaerobic sealant and have not had single "weeper" since....giant PITA to remove that gasket though...

to fix you will need a new set of 4 gaskets...clearanced OEM head, OEM base, OEM cam chain and OEM exhaust crush gaskets...oh yeah, and some Loctite 515...

my xr6 cometic is just that rubber fiber...I guess Im ok...

heart of darkness have you used a metal laminated BASE GASKET?

I love the info about the loctite anaerobic 515 sealant

I wondert if that can be used on our xrs sans a gasket?

good info zx!

Thinner gaskets would create more slack in the timing chain, moving the cam in the same direction as a worn/ stretched chain. I think it retards the timing.

For copper gaskets, there's an aerosol spray that's finely ground copper particles in a sticky adhesive.

I use that spray with varying degrees of success on my valve cover gasket and also on a barely used head gasket...the head gasket sealed well, the valve cover weeps at the front just a smidge...not enough to keep me from riding

I use that spray with varying degrees of success on my valve cover gasket and also on a barely used head gasket...the head gasket sealed well, the valve cover weeps at the front just a smidge...not enough to keep me from riding

I've also sprayed it on reused head and valve cover gaskets. It's worked three out of three times on oem head gaskets and one out of two times on oem valve cover gaskets.

I haven't yet used the Cometic coated metal base gasket. I guess the concept of a coated metal gasket works with new head and valve cover gaskets, so ought to work as a base gasket too. Maybe a fiber gasket can deform more easily on lower torque areas such as the outside of the cam chain slot.

yup

I reused a k and s head gasket which is almost IDENTICAL to oem...I would not for example use the copper spray on the cometic head gasket I have on there now

anyways I want so say Im sorry for these hijacks here

I will ask a question pertaining to this thread and that is does anyone or has anybody made a higher comp CAST piston for the xr600 model?

thanks

christian

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