Well, she finally puked her guts out.... (pic)

[spldart]

http://www.gz250bike.com/forum/showthread.php?t=7734

[Water Warrior 2]

So now that you are armed with new knowledge is it safe to say the whole procedure could be a one time R/R ?

[spldart]

Yes.
I've learned the whole job can be done in the bike.
I've learned shimming the head gasket makes the kit work.
I still dunno reliability.
Time will tell.

[spldart]

It will need a second shim.
I can very very faintly hear clearance issues at rev when warmed up.
Otherwise running great.

[Water Warrior 2]

Originally Posted by spldart

It will need a second shim.
I can very very faintly hear clearance issues at rev when warmed up.
Otherwise running great.

Tear down #5. I must compliment you on your patience and ability to solve a problem.

If it were me there would have been an accidental fire before teardown #3

[spldart]

Originally Posted by Water Warrior 2

Tear down #5. I must compliment you on your patience and ability to solve a problem.

If it were me there would have been an accidental fire before teardown #3

Why... Thank you!

I just finished putting in the second shim and decided to examine everything under magnification.
I have a crack starting at the spark plug hole and proceeding to one exhaust seat where it stops at the steel valve seat. The crack doesn't go through the head and I'm making compression so I'm thinking it's been slowly growing over time and prolly has nothing to do with the blown head gasket.
Another test drive tomorrow.

I'm thinking I'll keep this thing off the freeway from now on.
It took two hard years of freeway but that little motor isn't up for freeway long term.

[Water Warrior 2]

Gotta agree with staying off freeways. Far too fast and punishing to the GZ. The bike is wonderfully suited for secondary highways and are happy there.

[spldart]

Grabbed another 7 miles today.
Motor sounds very different than it used to.
It also shakes more at idle. Obviously the new piston isn't the same exact weight as the old one.
Motor is also making more heat due to more friction as it seats the rings. No biggie.

I did some searching on ebay and other places. Everyone is selling the same gaskets I got with this kit...
THAT'S TWO THIN!
The factory Zuki gasket is like 100 bux

[blaine]

Originally Posted by spldart

Grabbed another 7 miles today.
Motor sounds very different than it used to.
It also shakes more at idle. Obviously the new piston isn't the same exact weight as the old one.
Motor is also making more heat due to more friction as it seats the rings. No biggie.

I did some searching on ebay and other places. Everyone is selling the same gaskets I got with this kit...
THAT'S TWO THIN!
The factory Zuki gasket is like 100 bux

Can you use two of the Thinner gaskets or is that too thick??

[spldart]

Originally Posted by blaine

Can you use two of the Thinner gaskets or is that too thick??

The problem isn't the extra thickness... You might lose a tiny bit of compression but the bike would run.
The problem is the aftermarket gasket is composite-steel-composite from what I can see.
If you were to double that up I'm not sure heat would escape fast enough from the middle.
Old zuki gasket is all steel shim. No biggie. Heat transfers fast through metal.

If you sammich two ebay/china gaskets you would have *composite-steel-composite-composite-steel-composite*
That composite-composite interface in the middle having no direct way to get heat to the engine.

Heck. Old composite gaskets had a metal ringlet built around the cyl bore to deal with heat and pressure.
These cheap gaskets don't.

Perhaps I'm overthinking things a bit but I've seen enough failed engines that I think I have some loose grasp on how things work. Meh

All I can do now is keep you guys up to date on the longevity I get. Unless the head goes first