Attachment 333507
These are the ugly NSR heads with the offset plug that nobody seems to want. But they could be answer to my problem of how to get access to the combustion chamber to measure the combustion pressure so the EFI system knows if the motor has fired or not.
By a happy coincidence the pressure sensor neatly screws into the plug hole and the center of the combustion chamber has a cast in supported between it and the outside shell. It maybe enough to fit a 10mm central plug in. Two birds with one stone, pressure sensor and central spark plug.
Now to find another of these heads so I can cut it in half to see how much meat there is between the combustion chamber and outer head shell, enough for a 10mm plug I hope.....

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