Some 903cc questions

I need help figuring if these pistons will give me anything near the compression I need.

Does anyone know of a way I can figure out what the compression these pistons will be on a gpz750 head?

The only way is to install them and measure.

why not send the crank to Jay to be stroked while youre at it? go over 900cc. its just adding a cylinder spacer and retiming the cams(after you make sure everything has enough clearance)

If you take that route (and it won't be cheap) I'm told that GPz900R rods are 4mm longer, which would help with the rod/stroke ratio. They have the same size big end and the turbo size small end (16mm) though so you'd have to use pistons with that size pin.

I have been thinking of this, and the stroke/destroke issue. If I were to spend money I would go farther under square... for now at least I am going to leave the stroke as it is; until I can find a way to work the hp numbers for stroked vs de-stroked.

As for the compression, when I get time I will bother apejay and see if he can get me the dome displacement of those pistons; then I will check cometic and see what size head gaskets they offer. There is a good calculator online to tell the compression... hopefully when I get the numbers it will come out 9:1 or higher...

i dont see the need to destroke one of these motors. unless you plan on revving it to 13000, piston speed shouldnt really be the limiting factor with a mild stroke should it? im guessing stock revlimit would be plenty safe with a 3 or 4mm stroke. it would up the compression, and create a lot of tq