ADA Racing billet dome includes compression(OR042) and dome top(OR020) orings. Squish relief is .005 inch @ 82.5mm(fits up to 83mm piston) with a 4 degree angle. These domes fit our standard 750/800 head and our original girdled head with the billet brackets. See Related Products below.
Domes are sold individually.
All compression readings are at sea level on a stock, non-ported cylinder. Every 1000ft increase in elevation decreases the compression by 5-7lbs.
The stock head on a 2003 SXR800 measured 32.7cc with the head gasket(31cc head volume + 1.7cc gasket volume). The assembled volume was 35cc for an uncorrected compression ratio of 12.2:1. The stock squish clearance measured approximately 0.085" with a 0.035" relief in the stock head at 80.25mm diameter. The stock head gasket measured .0125" thick. Stock compression was 177psi in the front and 174psi in the rear, measured at 1200ft elevation. The top of the stock exhaust port measured 1.6" from the top of the cylinder.