Guys, my son is putting back together an '89 zilla top end, and I bought a copper head gasket for him. It was one that was thinner than normal that I thought we'd try as it would raise compression. My son cleaned the surfaces, installed the gasket and head and torqued to factory specs per the Suzuki manual. It leaked as soon as antifreeze was added back to the radiator. I wasn't completely suprised since the gasket was so thin. I ordered him another copper head gasket, this time a thicker one. Once again, it leaked as soon as he added the antifreeze.

This was not leaking before with the non-copper stockish style head gasket, so I don't think it's an issue with the surfaces not being flat. Do you guys use gasket sealer on these? Before I buy a third head gasket, I want to see if I can get one of these to work that I already bought.

Suggestions? If gasket sealer is the answer, what type would you recommend? If a non-copper head gasket is the answer, any particular one you would recommend or stay away from? What about torque specs? Do you guys go higher than what the book calls for? It has the factory stepped head studs that 88-90 have.

Also, the piston is a 87.5mm bore (1.50 oversize.) I was nervous buying just any gasket because I wasn't sure if a factory one would have a big enough diameter. The last copper one I bought specifically said it was good for 86mm - 88m (or 89mm, I can't remember), so I felt reassured that it would at least work size wise. And sure enough, it was big enough to clear the piston. I don't have a stock one to compare to, so I just wasn't sure if factory ones were limited to certain sized pistons.

Thanks!

I run a copper head gasket on my ATC250R. I've had the
head off and on at least a dozen times, same gasket and no leaks. You must use a sealer with with them. I use the Permatex copper spray can sealer.

Ok, thanks guys. I'll try some gasket sealer or copper spray. I'll also double check the surfaces.

Thanks,
yagerzzz

Just go with the oem gasket or the cometic, way to much stuff goes wrong with the copper gaskets.
I even think Mitch sells them in the store on here.

Good luck.

I've never had a problem with mine so far.

I did use a copper head gasket on mine.  The thing was a leaky POS.  I now have an o-ring head.

It has been my experience that copper is not resilient enough to conform and continue to exert enough force over the microscopic imperfections that appear when the engine is up to operating temperature and the distortion that occurs due to combustion pressure on each power stroke.  A head gasket has to be able to flex and conform to these moving surfaces over a hundred times per second to provide 100% sealing.

The quality of the sealant is what is largely responsible for the sealing action when a copper head gasket is used.  I do not recommend doing this ( has been done when doing dyno testing) but the copper gasket is basically a spacer and similar sealing results can be obtained using a good sealant between the head and cylinder providing the head was machine to provide the correct squish clearance and volume.

A rubber o-ring, conventional composition type head gaskets or stainless steel gasket that has embossed ribs do a much better job of  sealing of these moving sealing surfaces.

I agree 100%. Doesn't make sense to continually have to replace gaskets if it's not necessary. I'm gonna get it done near winters end.