Harley-Davidson CVO ROAD GLIDE Big Bore Kits

Genuine Harley-Davidson

3-7/8" Standard Bore. When combined with stock cylinder heads, these forged 3-7/8" pistons boost the compression ratio of your 3-7/8" big bore cylinder set-up. The combination results in a compression ratio of 10.5:1. Piston skirts feature a unique black coating for improved wear-resistance, better fit and reduced noise. These pistons include Titanium SST rings to withstand the stresses seen in racing. Complete kit includes pistons, rings, wrist pins and clips.

Genuine Harley-Davidson

When it comes to increasing engine power, there is no substitute for more cubic inches. With efficient filling of the air/fuel mixture, the bigger the displacement, the more power your engine can produce. In the past, the only way to increase the bore of your 96 or 103 cubic inch Twin Cam V-Twin motor was to tear down the motor and re-bore the engine cases to fit larger bore cylinder spigots. It was a labor-intensive and expensive process. Now, you can take your 96 or 103 cubic inch motor to a full 110 cubic inches without removing the engine from the chassis. The Screamin' Eagle team has engineered a 4" Big Bore Cylinder and Piston package that increase the internal bore from 3-7/8" to 4", without increasing the outside diameter of the cylinder spigot. The cylinder slips into the existing case bore without modification. This kit will add a whopping 7 cubic inches of displacement for more torque throughout the RPM range. The kit includes front and rear cylinders, system-matched pistons with rings and breathers.

Genuine Harley-Davidson

This multi-layered head gasket provides improved sealing for 3-7/8" Big Bore high performance engines. Sold in pairs.

Genuine Harley-Davidson

For the rider demanding no-compromise performance. This is the most displacement, and the most power, ever created by Harley-Davidson for a street-compliant crate performance engine. Engineered by the pros at Harley-Davidson and built from the bottom up in Milwaukee, this street-tuned 135-cubic-inch Screamin' Eagle Crate Engine is designed to run with a wide-open throttle at high engine speeds and provide instant passing power from cruising speed. Made for riders seeking maximum displacement, compression, and flow, it delivers 144 horsepower and 149 ft-lb of torque to the rear wheel. The 135ci engine compression ratio is 11.6:1. Exclusive 135 and Stage IV badging on the cylinder heads and timer cover highlight the powerplant. This street-ready performance motor features the finest Screamin' Eagle components. Many of these new components were informed by extensive testing by the Harley-Davidson Factory Racing Team for the King of the Baggers racing series. The 135ci Crate engine consists of: all-new Screamin' Eagle Extreme CNC-ported cylinder heads, new SE8-550 high-lift cam, new high-compression forged pistons, 68mm throttle body and new CNC-machined Extreme Flow 68mm intake manifold, high-performance cam bearing, high-performance tappets, new patent-protected 4.31" steel sleeve cylinders, 4 5/8" flywheel, 6.8 g/sec fuel injectors, and Screamin' Eagle Pro Billet Cam Plate and Oil Pump. Black Granite / black finish. Engineered and tested as a complete collection of high-performance components by the Screamin' Eagle pros at Harley-Davidson. This combination is designed for wide open throttle along with high end RPMs and a significant torque increase from a cruising speed. Ready for bolt-in installation in the Original Equipment-style chassis of your Touring bike. For models originally equipped with Variable Valve Timing (VVT), VVT will not be retained with this performance crate engine. No special fabrication or engine-mount relocation is required. Factory assembled at the Powertrain Operations facility in Milwaukee, Wisconsin.

Genuine Harley-Davidson

The most advanced Twin Cam performance cylinder head design available. Screamin' Eagle CNC Ported Maximum Velocity Area (MVA) cylinder heads create power across the entire RPM range by maximizing velocity through the intake ports. Increased air speed velocity through the ports is achieved by "right sizing" port volume at 98cc, lowering the port roof, and by precision-machining the shape of the port to complement the giant 2.120" intake valves. Screamin' Eagle CNC-Ported MVA Cylinder Heads conquer a unique engineering challenge, and provide the highest possible torque and acceleration at any RPM. MVA Heads will boost the punch of a 103" engine. When paired with high lift cams, MVA Heads can give a 110" or 113" motor everything it needs to achieve new levels of performance. Countless hours of dyno testing resulted in a 95cc combustion chamber that performs in perfect balance with the port size and shape, and reduced detonation. MVA Heads feature Screamin' Eagle Race Springs that permit the use of high lift cams (up to.660"), and are machined to accept automatic compression releases (sold separately) for easier starting. MVA Heads are manufactured and assembled at Harley-Davidson's world class engine factory in Milwaukee, ensuring every set is made to exact tolerances.

Genuine Harley-Davidson

Screamin' Eagle Stage III - 121ci to 125ci

Genuine Harley-Davidson

For the rider demanding no-compromise performance. This is the most displacement, and the most power, ever created by Harley-Davidson for a street-compliant crate performance engine. Engineered by the pros at Harley-Davidson and built from the bottom up in Milwaukee, this street-tuned 135-cubic-inch Screamin' Eagle Crate Engine is designed to run with a wide-open throttle at high engine speeds and provide instant passing power from cruising speed. Made for riders seeking maximum displacement, compression, and flow, it delivers 144 horsepower and 149 ft-lb of torque to the rear wheel. The 135ci engine compression ratio is 11.6:1. Exclusive 135 and Stage IV badging on the cylinder heads and timer cover highlight the powerplant. This street-ready performance motor features the finest Screamin' Eagle components. Many of these new components were informed by extensive testing by the Harley-Davidson Factory Racing Team for the King of the Baggers racing series. The 135ci Crate engine consists of: all-new Screamin' Eagle Extreme CNC-ported cylinder heads, new SE8-550 high-lift cam, new high-compression forged pistons, 68mm throttle body and new CNC-machined Extreme Flow 68mm intake manifold, high-performance cam bearing, high-performance tappets, new patent-protected 4.31" steel sleeve cylinders, 4 5/8" flywheel, 6.8 g/sec fuel injectors, and Screamin' Eagle Pro Billet Cam Plate and Oil Pump. Black highlights & black finish. Engineered and tested as a complete collection of high-performance components by the Screamin' Eagle pros at Harley-Davidson. This combination is designed for wide open throttle along with high end RPMs and a significant torque increase from a cruising speed. Ready for bolt-in installation in the Original Equipment-style chassis of your Touring bike. For models originally equipped with Variable Valve Timing (VVT), VVT will not be retained with this performance crate engine. No special fabrication or engine-mount relocation is required. Factory assembled at the Powertrain Operations facility in Milwaukee, Wisconsin.

Genuine Harley-Davidson

For the rider demanding no-compromise performance. With the largest displacement and the most power of any Harley-Davidson Stage Kit, this 121ci to 135ci Stage IV Kit was engineered by the pros at Harley-Davidson to deliver instant arm-stretching torque through the entire rpm range. Made for riders seeking maximum displacement, compression, and flow, it delivers 144 horsepower and 149 ft-lb of torque to the rear wheel. This Stage IV Kit features the finest Screamin' Eagle components. Many of these new components were informed by extensive testing by the Harley-Davidson Factory Racing Team for the King of the Baggers racing series. The Stage IV kit consists of all-new Screamin' Eagle Extreme CNC-ported cylinder heads, 68mm throttle body and new cast 68mm intake manifold, new SE8-550 high-lift cam and 6.8 g/sec fuel injectors that work together to feed the engine large volumes of air and fuel to help maximize power. New forged high-compression pistons and rings are designed to withstand increased combustion forces. Also includes high-performance tappets, new patent-protected 4.31" steel sleeve cylinders, and Screamin' Eagle Pro Billet Cam Plate and Oil Pump. Screamin' Eagle and Stage IV badging on the cylinder heads and timer cover highlights the powerplant. Black Granite. Engineered and tested as a complete collection of high-performance components by the Screamin' Eagle pros at Harley-Davidson. This combination is designed for wide open throttle along with high end RPMs and a significant torque increase from a cruising speed. Provides thrilling acceleration when twisting the throttle. Can be installed without removing the engine from chassis. For models originally equipped with Variable Valve Timing (VVT), VVT will not be retained with this performance Stage IV kit. Race only.

Genuine Harley-Davidson

For the rider demanding no-compromise performance. This is the most displacement, and the most power, ever created by Harley-Davidson for a street-compliant crate performance engine. Engineered by the pros at Harley-Davidson and built from the bottom up in Milwaukee, this street-tuned 135-cubic-inch Screamin' Eagle Crate Engine is designed to run with a wide-open throttle at high engine speeds and provide instant passing power from cruising speed. Made for riders seeking maximum displacement, compression, and flow, it delivers 144 horsepower and 149 ft-lb of torque to the rear wheel. The 135ci engine compression ratio is 11.6:1. Exclusive 135 and Stage IV badging on the cylinder heads and timer cover highlight the powerplant. This street-ready performance motor features the finest Screamin' Eagle components. Many of these new components were informed by extensive testing by the Harley-Davidson Factory Racing Team for the King of the Baggers racing series. The 135ci Crate engine consists of: all-new Screamin' Eagle Extreme CNC-ported cylinder heads, new SE8-550 high-lift cam, new high-compression forged pistons, 68mm throttle body and new CNC-machined Extreme Flow 68mm intake manifold, high-performance cam bearing, high-performance tappets, new patent-protected 4.31" steel sleeve cylinders, 4 5/8" flywheel, 6.8 g/sec fuel injectors, and Screamin' Eagle Pro Billet Cam Plate and Oil Pump. Black highlights & chrome finish. Engineered and tested as a complete collection of high-performance components by the Screamin' Eagle pros at Harley-Davidson. This combination is designed for wide open throttle along with high end RPMs and a significant torque increase from a cruising speed. Ready for bolt-in installation in the Original Equipment-style chassis of your Touring bike. For models originally equipped with Variable Valve Timing (VVT), VVT will not be retained with this performance crate engine. No special fabrication or engine-mount relocation is required. Factory assembled at the Powertrain Operations facility in Milwaukee, Wisconsin.

Genuine Harley-Davidson

For the rider demanding no-compromise performance. This is the most displacement, and the most power, ever created by Harley-Davidson for a street-compliant crate performance engine. Engineered by the pros at Harley-Davidson and built from the bottom up in Milwaukee, this street-tuned 135-cubic-inch Screamin' Eagle Crate Engine is designed to run with a wide-open throttle at high engine speeds and provide instant passing power from cruising speed. Made for riders seeking maximum displacement, compression, and flow, it delivers 144 horsepower and 149 ft-lb of torque to the rear wheel. The 135ci engine compression ratio is 11.6:1. Exclusive 135 and Stage IV badging on the cylinder heads and timer cover highlight the powerplant. This street-ready performance motor features the finest Screamin' Eagle components. Many of these new components were informed by extensive testing by the Harley-Davidson Factory Racing Team for the King of the Baggers racing series. The 135ci Crate engine consists of: all-new Screamin' Eagle Extreme CNC-ported cylinder heads, new SE8-550 high-lift cam, new high-compression forged pistons, 68mm throttle body and new CNC-machined Extreme Flow 68mm intake manifold, high-performance cam bearing, high-performance tappets, new patent-protected 4.31" steel sleeve cylinders, 4 5/8" flywheel, 6.8 g/sec fuel injectors, and Screamin' Eagle Pro Billet Cam Plate and Oil Pump. Black Granite / Chrome finish. Engineered and tested as a complete collection of high-performance components by the Screamin' Eagle pros at Harley-Davidson. This combination is designed for wide open throttle along with high end RPMs and a significant torque increase from a cruising speed. Ready for bolt-in installation in the Original Equipment-style chassis of your Touring bike. For models originally equipped with Variable Valve Timing (VVT), VVT will not be retained with this performance crate engine. No special fabrication or engine-mount relocation is required. Factory assembled at the Powertrain Operations facility in Milwaukee, Wisconsin.