Leak in the cylinder head

Both these KZ/Z400s have had complete Engine Rebuilds. The Blue one is the Early Type 74/77 and Started life in the US it now has the Later 1978 Z400 Engine Fitted the other is a 79 and the Original Engine was far to Gone so the one in it is built mainly from Refurbished and N.O.S Parts if you look at KZ400.com you will find the full Z400 Engine Rebuild
( www.kz400.com/EnginemodificationFrameset.html ) the Replacement of the Rocker Gasket is Straightforward and only the Tank needs Removing. The Z400 Engine is very easy to Work on and the only special tools needed are the tool to remove the Rotor and a good set of Cire clip Pliers internal and External . This Site will also give you all you need to know regarding KZ/Z400s and 440s.

 

I would add to that tool list a good torque wrench.  Too many stud holes have been stripped by backyard mechanics guessing at how tight a bolt should be.

And some JIS screwdrivers. 

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Conventional wisdom says that the k designation was not used in Europe due to the connection between the letters KZ and the NAZI regime.
 

Kz is the abbreviation for the German word for concentration camp.

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Thank you.

What is that kind of gasket called?

 Realize also that when the cylinder head cover is loosened then the entire top end should come off because the head gasket and base gasket are likely to leak after the clamp load is removed.  

That is true for the early 400 but not the late 400/440. The head stud nuts are under the rocker box.

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Thank you.

What is that kind of gasket called?

I believe it is called the rocker box gasket.

Hi Jon,just noticed your thread...
last year I had same problem on my z400 d4 1978,when I rebuilt top end,I never used any silicon plus head gasket...
were Led to believe not to do it,but as the z400 are prone to leaks around these areas,I'd advise some sealant ..
what you want is threebond 1215..
good stuff...
also,try make sure you use kawasaki head gasket & not remade  replica,as can be not as suitable...
I got good results,no leaks,on 2nd rebuild,with silicon,after lots research...
Make sure your torque wrench is calibrated too...
only small amount needed to make good seal....
Hope this helps you...
All the best...
Shane..

I have replaced many Rocker Box Gaskets over the last 30 Years and most I have made myself from good Gasket Paper and without and problems on both Early KZ/Z400 1974/77 and Z/KZ400 1978/79  along with 1980/84 Z/KZ440s none caused any problems and all where oil tight after.
I run a 81 A2 that I have had now for over 35 Years it is fitted with a D2 Engine at the moment with a 2 into 1 System running a Goldstar Silencer. 
 

Yes a Torque Wrench is a must for this and any other Engine Build.