90″ Sportster Monster Big Bore Kit – Natural

Fits 1991-2020 XL  motorcycles – 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. Additional upgraded services recommended. – Includes pair of all-aluminum NSC-coated bore cylinders, custom-forged pistons with high-tension rings specifically designed for SNC cylinders and a head/base gasket set – Replacement gasket sets available separately – Upgraded cylinder studs and head bolts recommended – Made in the U.S.A.