cylinder head hair line cracks

[slappa13]

Hi Guys
Started to refurb my z1000a2 cylinder head today, noticed small cracks between valve seats and sparkplug holes is this normal in z1000s.
Neil

[Pigford]

.....it's not uncommon - can be repaired - get a specialist to check it out, like SEP

[zed1015]

Very common and very unlikely to turn in to something nasty .
They are mostly just surface cracks and usually only extend to about a mill deep.
There are stories of them causing loose valve seats but i've never seen it and i've built and owned tons of zeds.
My own everyday zed has these on a couple of cylinders with no problems in 14 years of everyday use.
If you really want to waste money they need to be welded up which means removing the seats then recutting the head for new seats after welding.

[Big Fluff]

Agree with Rob, I've had a few heads like this, my Phil Manzano head being the worst, but it never gave any problems.
Just let the carbon do it's job and keep an eye out for loosening spark plugs