what makes a head gasket leak?

1984 GPZ1100
I bought this bike semi disassembled...
previous owner broke a head stud while attempting to change the head gasket... gave up and sold it to me. (cheap)

I put it all back together with APE studs and nuts... but foolishly used the same head gasket he was using.
sprayed it with copper spray ... which didnt help

and of course it is leaking again...
not a big deal... I now have a new head gasket...

but I am wondering if maybe the head is warped?

is there a way to check the head/cylinder mating surface to be sure?

Or would I need to bring it to a machine shop for a special procedure?

I'd hate to do the gasket and have it leak again..

otherwise, the bike runs great... I rejetted the carbs with 140 mains and 40 pilots... pod filters and kerker 4 into 1 with no baffle...
runs great...

thanks for any help.

a couple pics of each side.
seems to be leaking at each end , where the smaller bolts are.

as you'll notice, the right side smaller bolt has a nut on the bottom.. the hole felt like it was beginning to strip so I put in a longer bolt and put a nut on the bottom.
and torqued it according to the kawi. specs.

Uploaded with ImageShack.us

Uploaded with ImageShack.us

never reuse head gasket, buy new one torque correctly, no leaks

John T wrote:

but I am wondering if maybe the head is warped?

is there a way to check the head/cylinder mating surface to be sure?

steel straight edge laid across in several angle directions

The answer to your question is my friend John. He's blown two this year.

if the head and block surfaces are square. once you have run the motor for a few heat cycles retourque the head nuts again that should stop it from leaking.

You need to jump on the retorque after the first heat cycle.

What kind of head gasket ?

If you swap it again, have the head surfaced & not on a belt sander.

larrycavan wrote:

What kind of head gasket ?
some kind of aftermarket composite 2 piece. not sure the brand.. I now have a stock kawasaki head gasket

If you swap it again, have the head surfaced & not on a belt sander.what method would you recommend?

larrycavan wrote:

...retorque after the first heat cycle....

Here's one method:

Upon completing reassembly and running engine one time long enough to attain normal operating temperature (say, take an easy little ride), then allow the engine to cool overnight.

Next morning, on cold engine, re-torque the head in the pattern specified by the FSM.

When re-torquing, just tighten to spec. Don't first back off a little before re-torquing.

It's okay if the nut doesn't further tighten during the re-torque.

Good Fortune!

Perhaps of interest, some general basics:
Click > www.aa1car.com/library/ar996.htm

Not a diy job, imho (at least for me).

Good Fortune!