Old Zed - Cyl head cracks worse than usual?

[TiBolts]

After getting my Z1000-A1 head back from vapour blasting the clean combustion chambers now reveal the usual cracks on 3 of them... I know from of old (and from searching this forum) that this isn't usually the end of the world, but one of these cracks looks quite bad. What do you Zed heads think? Cheers
PS photo taken with 'proper' camera with macro lens, so the truth in all its naked ugliness is revealed...

[Ultim8pc]

Noting to worry about. I've seen them get half way up the plug hole, but never beyond that. You can weld them up but it's not worth it IMHO.

[zed1015]

As above.
Surface expansion cracks.
Seen much worse .
Run it.

[needaz1100r]

The only issue I've seen that cause is a build up of carbon that sticks to the plug. I've seen it bad enough to need an impact gun to get the plug out, but it didn't pull the threads out like I thought it might.

On that one, personally, because of the state of the threads AND the crack I would Time-Sert it.

However, that's a personal preference and I wouldn't say any of the previous replies should be discounted, you could definitely run that as it is with no issues.

[Mr Bump]

Noting to worry about. I've seen them get half way up the plug hole, but never beyond that. You can weld them up but it's not worth it IMHO.

The original head on my Z1000a1 had cracked all the way up no 3 plug thread and on down the exhaust port. I sh*t thee not. Exhaust valve seat was distorted too.

I think that was a pretty extreme case though.

[TiBolts]

Cool. Thanks guys for the comments. Also a mate of mine has been running one for many years like this and has had no problems.

Best get on with putting the rest of the motor together now then!