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HOME » 1250 Bolt-On Big Bore Kit

Revolution Performance 1250cc Bolt-On Big Bore Kit

(Fits 1986-present Sportster, XB and XR1200 style Harley Davidson motorcycles)


The Revolution Performance 1250cc Sportster, XB and XR1200 Bolt-On Big Bore Kit is the most reliable way to increase power and torque on your 1986-present Sportster, XB and XR1200 style engine. Each kit comes with our state of the art all aluminum NSC plated cylinders which last longer and run cooler than the OEM cylinders. The cylinders are matched with a premium forged piston available in two different compression ratios and a Cometic head and base gasket kit.

    1250cc Bolt-On Big Bore Kit comes with:

  • NEW 3.563" all aluminum Nickel Silicon Carbide (NSC) plated cylinders in your choice of finish: All Black, Black Highlight or Natural
  • Forged 10:1 compression ratio flat-top pistons or optional 11.0:1 dome-top piston kit(+5cc)
  • Cometic head and base gasket kit (.027 head gasket / .018 base gasket)
  • The 1250cc Bolt-On Big Bore Kit requires no other engine modifications to install but can benefit from our other products and services.

    Recommended Services:

  • 1250cc CNC Cylinder Head Porting Package

    ***NOTE: Compression ratio is dependent on the cylinder heads combustion chamber volume***

    ***NOTE: Dyno chart represents 1250cc Bolt-On Big Bore Kit, Velocity CNC ported heads, Feuling .505 cams, RC Components Air Cleaner and Bassani 2-into-1 exhaust***

For questions on our big bore kits, please contact our sales technicians directly at: 1-866-892-2109 M-F 8:30 A.M. - 5:00 P.M. CST.

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