Revolution Big Bore Monster Cylinder Kit 131" Cut Granite Harley Twin Cam 99-17BRAND NEW PART# RP201 135W 131" kit for 99 17 Twin Cam S&S 4 1 4" bore 4 5 8" stroke w. 7. 669" rods; 11. 2: 1cr (w 86cc heads); 10. 6: 1cr (w 95cc 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