Revolution Big Bore Monster Cylinder Kit 90"" Silver Harley Sportster XL 91-20
Designer: Revolution Performance
- Unit Price
Free delivery to the Lower 48 States
30 Day Returns and Exchanges
Fitmet Questions? Call us at 610-754-8500
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.S.A.
BORE SIZE 3.875"
STROKE LENGTH 3-13/16"
COMPRESSION RATIO 10.5:1