TOPIC:

ok about 0.4 - 0.5mm I guess allow about 0.1mm for the paint., so maybe around 0.5mm Are the combustion chamber cc within spec?

Getting 1.0 mm on my GPz1100 B head, don't think it has been skimmed.

I think the number's will come up diff, depending on what head you have.
I don't think comparing a KZ550 head to a KZ1000 would give valid info.

Let's start a list of what the head's you have come up.
I did a quick measure on both my GPz750 head's tonight.
'83 ZX750A1 .035
'84 ZX750A2 .035

does it look as tho the pads were machined from the factory?
or are they as cast?

leon

p.s.
cc'ing the combustion chambers is probably the best way to decide what you believe has been done to them

They don't appear to be machined, but they are smoother than the fin surface around them, so maybe they aremachined or at least a very smooth part of the casting. I'm not even sure they are actually parallel to the head surface. It looked like one edge had more gap than the other edge, but that could have been an optical illusion, or due to the paint or corrosion, in my case.

it seems unlikely the factory would use an as cast finish for a reference point,considering casting shrinkage.

leon

Is it possible that pad was for some other purpose, like maybe to help with pulling the head?

I would think that the best reliable ways to test for a cut head would be to cc the chamber and compare that to a known stock head....or measure from the cam cover gasket surface to the head surface and compare to a known stock head.

I'm surprised at the total lack of chamber cc numbers for stock KZ heads on any forum. I guess since no one likes cutting heads, they just run pop up pistons and go with the manufactures rated compression ratio,

Just seems odd compared my past experience building car engines for performance applications.

tachrev wrote: I would think that the best reliable ways to test for a cut head would be to cc the chamber and compare that to a known stock head....or measure from the cam cover gasket surface to the head surface and compare to a known stock head.

I'm surprised at the total lack of chamber cc numbers for stock KZ heads on any forum. I guess since no one likes cutting heads, they just run pop up pistons and go with the manufactures rated compression ratio,

Just seems odd compared my past experience building car engines for performance applications.

Covered in FSM for 1977~1979 KZ1000:





Good Fortune!

Wow, incredible. Good to know!

It's not in the Z1 manual, I checked. It is in one of the I model manuals I've seen (39.5-40.3ccs)

Thanks.

so that is a start, any more cylinder heads to measure? 5 minute job with a straight edge and feeler guage.

Another method might be finding the total height of the head by using verniers in the camchain tunnel.

Working out CR and dialing in cams isn't for everyone and if there is a sure fire way of measuring as to how much a head has been skimmed it would be good to know.

Could these square pads not be skim markers, but where something from the casting manufacture?

Does anyone here have any zx550 and or gpz11 b head they could measure total thickness of, through the camchain tunnel with verniers,plus the clearance between the gasket face and this mystery square pad?

Those pads are not skim markers, just remnants of the casting process.
Only way to check for skimming is combustion chamber volume and appearance of the gasket face.