Revolution Big Bore Monster Cylinder Kit 90 Silver Harley Sportster XL 91-20

  

90" kit for 91-20 Sportster 3-7/8" bore 3-13/16 stroke 10.5:1cr (w/ 62cc flat-top heads); 9.8:1cr (w/ 95cc dished heads). Aerospace-grade all-aluminum cylinder with nickel-silicon-carbide (NSC) electroplated bore No sleeving allows for larger bore sizes NSC-plated cylinders have less friction for increased horsepower, lower engine temperatures and a longer lifespan Monster big bore kits will require case boring Includes pair of all-aluminum NSC-coated bore cylinders, custom-forged pistons with high-tension rings specifically designed for NSC cylinders and a head/base gasket set Replacement gasket sets available separately Upgraded cylinders studs and head bolts recommended Made in the U. COLOR/FINISH NATURAL BORE SIZE 3.875" DISPLACEMENT 90" STROKE LENGTH 3-13/16 COMPRESSION RATIO 10.5:1.