[GG27]

I just measured my cylinder head squish band and it is 1.83mm with a .5mm base gasket! Stock it had both .5mm + .3mm gaskets so the stock squish must have been over 2mm!. No wonder I couldn't get my jetting right. It got better when I removed the .3mm base gasket but still no where near what this engine can produce.

Since I have opened up the engine for a piston change and I know the ideal squish is between 1.4 and 1.5mm should I mill .1mm from the head and use the .3mm gasket or shouldI use the .15mm gasket? My mechanic thinks that I will blow the engine if I go down to a 1.4 squish by too much compression.

Also how can I measure the Combustion chamber volume to the ideal 21.5cc?

Can I just blank of the spark plug hole and fill the cylinder head with a syringe till the water reaches the circumference of the head? If I get hold of a pressure tester what is the ideal compression in psi, 185?