Shaved heads

When shaving the cylinder head, what must be changed along with it? Rejetting, timing, anything like that?

Depends on how much is shaved, but shave too much and there may be problems with the valves. What is the reason for wanting to shave the head? Ed

On an overhead cam engine the can timing will retard when the head or deck is milled.
Static compression ratio will increase because of less volume in the combustion
chamber. Cylinder pressure, as checked with a compression gauge, will also increase
because the intake valve closing earlier. And cam overlap, depending on if it is a single
or double overhead cam, to a lesser degree affects cylinder pressure.


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You will also have to degree your cams if you do this.

You can mill the head. We are talking thousands of an inch here ok. The goal is taking off the minim possible and not another thousand.

I had .65 thousand taken off of mine during rebuild to correct a low and high spot.

If you have base damage and need to have a larger amount taken off....you can get oversize gaskets to return you to a proper valve - piston clearance and compression.

DO YOUR HOMEWORK Create a 100% bullet proof plan and follow it to the tee. Find a professional machine shop that wont screw you or your stuff up. Ask tons of questions and ck out their work.

two ways to get there.....imo....mill head or thinner base gasket, on a Z oem base gasket .020 is stock thickness if memory serves me :pinch: you can buy .005 and .010 (copper)and stack or remove to get your desired height :S or run no base gasket at all...it depends on your cylinder .... :blink: your engine will run better if you can get it a few thousandths down the hole or as close to zero deck as clearances allow :woohoo: re-degreeing the cams and checking valve to valve and valve to piston clearance goes without saying along with maybe a ignition timing adjustment ..... :lol:

Had APE cut mine down the min which turned out to be .004 on my KZ650. Cleaned up perfect but probally didn't do much for the compression. Mainly Didn't want to do the slotting of the sprockets and degreeing.

4TheKZ1000 wrote:
I had .65 thousand taken off of mine during rebuild to correct a low and high spot.

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Damn decimal point. :woohoo:

Nebr_Rex wrote:

4TheKZ1000 wrote:
I had .65 thousand taken off of mine during rebuild to correct a low and high spot.

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Damn decimal point. :woohoo:

No doubt. Less than one thousandth. How could they tell it needed it? :huh:

650ed wrote: What is the reason for wanting to shave the head? Ed

I'm going to have my head off the block for awhile and was wondering if it would be worth the trouble. They talk about it often on GPZfaq so I got curious.

When taking off the minimum, is there a noticeable power increase, or does the increased compression make it run poorly?

Any references so I can "do my homework" would be much appreciated.

freakinbike wrote:

650ed wrote: What is the reason for wanting to shave the head? Ed

I'm going to have my head off the block for awhile and was wondering if it would be worth the trouble. They talk about it often on GPZfaq so I got curious.

When taking off the minimum, is there a noticeable power increase, or does the increased compression make it run poorly?

Any references so I can "do my homework" would be much appreciated.

you wont notice a thing. Will just help things seal up better is all.

It's all in the math. 750s are 738cc, combustion chamber is around 26cc.
The chamber on the later heads (GPZ) are 65mm necking down to 61mm
in 1/8 in.. You can guesstimate by doing the math. Or you could d'o a search
on the site because it's been talked about before.



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