I have an S3 head. The higher compression inserts certainly have less squish clearance, I got my squish down to about 1.6 with a thin base gasket and the AA insert (highest comp) Runs great @ 3000 - 7000 feet on 91, any lower and you will surely need better fuel.
I believe the coolant flow is improved as well, I rarely boil over any more.
__________________
2021 Beta 300RR
2014 Gasgas XC300R
2019 850 Pro RMK
|