General Squish Question

[Ruf Racing]

Just rebuilt the top end on a 87' KX80 the squish is .040 with 150psi. Does the rule of thumb to keep the squish around .050 and the psi under 180 for pump gas, apply to all 2 strokes? Thanks.

[LONG-ROD]

I just rebuilt a cr 80 and it had 170 lbs. not sure of the squish. .40 will be fine. you dont really want much less.

[machwon]

The "rule of thumb rule" parameters you mentioned does not work too well outside the 250cc stuff, even then it can cause problems and be very borderline. a .050 squish would be very loose on a built 50cc motor and too tight on a 500cc motor. Cranking psi is another misleading measurement as say a ported banshee motor may have only 135 psi and require 110 octane, while the same head on a pair of unported stock banshee cylinders would have 175 psi and still require the 110 octane. Exhaust port height can have a big effect on the static psi reading you get on a compression guage.

[Ruf Racing]

Ok, thanks guys.