Z1r z1000 cylinder head

[SuffolkZ1r]

Hi guys.

Looking for a cylinder head for my Z1R . Unfortunately after stripping and finding out mine has at some stage overheated and has cracks from spark plug holes to valve seats !
Gutted, as renovation was coming on so well until discovered this !
Anyone got one lying around that I could buy?
Thanks Gary

[Garry.L]

Hi guys.

Looking for a cylinder head for my Z1R . Unfortunately after stripping and finding out mine has at some stage overheated and has cracks from spark plug holes to valve seats !
Gutted, as renovation was coming on so well until discovered this !
Anyone got one lying around that I could buy?
Thanks Gary

From memory the cracks between valves and plug holes are quite common and nothing to much to worry about?...

[zed1015]

The surface expansion cracks are very common and 99.9 times out of 100 are not an issue.
There's more heads out there with cracks than without so don't dismiss the head for no reason.

[neilbarrett]

You be very lucky to get a head needing no work.once sold one of a running motor to someone on here and his engine builder charged him about 300 for extra work .the buyer had a moan at me .

[Gray17]

Hi I have just gone through this with my own Z900 A4 cylinder head which also suffered stress cracks in the plug thread area. Not sure how bad yours are but i posted photos on the help section of mine and teceived the same advice as they are common, Mine also ran ok with the cracks.
As luck would have it i stripped mine for vapour blasting which is how i discovered them. So whilst apart had the ex guides replaced and seats recut (inlets were ok) and a head skim at the same time the engineering firm fitted 2 time serts to the plug area which appears to have eliminated the cracks. It was then pressure tested. So if youre concerned you could do this.
As a side note others suggested getting the cracks Tig welded, i contacted several specoalist welding places 1 refused to work on the head, another wanted £3000 for the work which is a ludicrous price? You can also buy brand new ones from Kawasaki as theyv re cast them. Personally i think the advice given is correct in that the cracks unless really bad are indeed common in a 40+ year old motor and engine runs fine with them.
So it comes down to how big your pockets are versus how concerned you are about the cracks or just live with them as im sure most do.

[SuffolkZ1r]

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Thank you all very much for your replies.
This certainly fills me with some hope going forward. I have put some pictures of the damage. The head has been vapour blasted as you can see, the damage was not visible before doing so.
What are your thoughts after seeing these?
I really appreciate the feedback, thanks again guys.

[SuffolkZ1r]

Meant to mention, that prior to strip down the bike seemed to run fine albeit a small amount of smoke after revving up high. I put this down to maybe hardened valve guides through lack of use by previous owner? The plan is to replace them and grind and re seat the valves.
Thanks again

[Gray17]

If you look at the bike help section, my post on cylinder head, i have put a photo of mine which looks very similar to yours, in my case it was just 2 plug holes that were effected.
Later on in the post i have put another photo after the eng work was done. So you can see a before and after. Again like you i didnt notice these fractures until after the vapour blasting was done, my gues they were filled with carbon and masked or maybe even opened up more?
Think as others have stated if you get a used head it will probably have similar cracks unless you get one thats been fully refurbed or engineered which wont be cheap.
When i first saw mine i incorrectly assumed that the head had new ( poorly fitted) hardened seats fitted and the cracks had hapoened then but apparently thats how they came from the factory. To my mind the valves are either slightly too big or the plug should be set back slightly to give a bit more meat around the area when it was designed. Of course it cant be altered now!
Ps you may be better posting in the help section as may get more comments.

[Big Fluff]

I have a very nice and complete head that I covered in ACF50. Don't think it's a D1 head but 99% sure it's an A2 head so you'd need to flat the outer fins and paint it black.
It's complete as in followers & matching caps (maybe even valve train, can't remember but can look).
I also have spare cams, cam cover & more.
If you want me to check it out further then please get in touch.
Regards, Will.

[SuffolkZ1r]

Cheers again.
Will, you have a PM. Cheers.

[SuffolkZ1r]

Hi Will. Big Fluff.
Have been trying to send you an email and various PM ‘s but they keep going to my outbox ? I have also tried sending to an administrator and the same?
I am interested in the Z1 cylinder head , could you try messaging me please?
Thank you, Gary

[Garry.L]

Hi Will. Big Fluff.
Have been trying to send you an email and various PM ‘s but they keep going to my outbox ? I have also tried sending to an administrator and the same?
I am interested in the Z1 cylinder head , could you try messaging me please?
Thank you, Gary

When you send a PM it stays in your outbox until the recipient actually reads it. 'Then' it will show as sent.

[SuffolkZ1r]

Cheers for that Garry, Will has just contacted me.