Harley-Davidson Accessories Big Bore Kits

Showing 1–48 of 58 Screamin' Eagle Performance by Harley-Davidson Accessories

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.

Harley-Davidson Accessories

#16200977

£8417.99£7576.19

Member£7155.29-15%

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.

Harley-Davidson Accessories

#16200978

£8417.99£7576.19

Member£7155.29-15%

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.

Harley-Davidson Accessories

#16200979

£8417.99£7576.19

Member£7155.29-15%

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.

Harley-Davidson Accessories

#16200980

£8417.99£7576.19

Member£7155.29-15%

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 143 ft-lb of torque to the rear wheel as soon as the throttle is cranked. The Stage IV equipped engine includes 135 Stage IV badging on the cylinder heads and timer cover to highlight the powerplant. This street-ready performance motor features the finest Screamin' Eagle components: Screamin' Eagle Extreme CNC-ported cylinder heads, SE8-517 high-lift cam, new high-compression forged pistons, high-performance cam bearing, high-performance tappets, patent-protected 4.31" steel sleeve cylinders, new 4 5/8" flywheel, new 68mm throttle body and CNC-machined 68mm intake manifold, new 6.8 g/sec fuel injectors, and Screamin' Eagle Pro Billet Cam Plate and Oil Pump. Chrome finish.

Harley-Davidson Accessories

#16200985

£7987.22£7188.50

Member£6789.14-15%

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.

Harley-Davidson Accessories

#92500143

£4725.41£4252.87

Member£4016.60-15%

For the rider demanding no-compromise performance. This 117ci to 131ci 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 131 horsepower and 139 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 and new patent-protected 4.31" steel sleeve cylinders. Screamin' Eagle and Stage IV badging on the cylinder heads and timer cover highlights the powerplant. Black Highlighted. 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. Race only.

Harley-Davidson Accessories

#92500144

£4208.96£3788.06

Member£3577.62-15%

This Stage IV Kit was designed to deliver maximum horsepower - all the way to the redline. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. Coupled with the kit's high-lift SE8-517 cam, high compression pistons and a 64mm throttle body and intake manifold, this combination delivers a thrilling 126 ft-lb of torque and 121 HP rear-wheel output when paired with Screamin' Eagle Street Cannon Mufflers. It's designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You'll feel the difference as soon as you twist the throttle. When installed by an authorized Harley-Davidson Dealer within 60 days of the vehicle purchase, compliant kits do not impact the vehicle's limited warranty. Kit includes CNC Ported Cylinder Heads with CNC machined chamber and 1mm larger valves L93, Stage IV Timer Cover, SE8-517 High-Lift Cam, Forged High Compression Pistons, High Performance Cam Bearing, Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold and High Flow Injectors (5.5 g/sec). Stage IV Kit - 114CI to 128CI for Twin-Cooled models. Delivers increased response throughout the entire RPM range. Provides thrilling acceleration when twisting the throttle. Maintains flat torque curve from cruising RPM to redline. Can be installed without removing the engine from chassis. Retains Original Equipment Factory Warranty. 49-State U.S. EPA Compliant on '17-later Touring models.

Harley-Davidson Accessories

#92500077

£3944.54£3550.09

Member£3352.86-15%

This Stage IV Kit was designed to deliver maximum horsepower - all the way to the redline. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. Coupled with the kit's high-lift SE8-517 cam, high compression pistons and a 64mm throttle body and intake manifold, this combination delivers a thrilling 126 ft-lb of torque and 121 HP rear-wheel output when paired with Screamin' Eagle Street Cannon Mufflers. It's designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You'll feel the difference as soon as you twist the throttle. When installed by an authorized Harley-Davidson Dealer within 60 days of the vehicle purchase, compliant kits do not impact the vehicle's limited warranty. Kit includes CNC Ported Cylinder Heads with CNC machined chamber and 1mm larger valves L93, Stage IV Timer Cover, SE8-517 High-Lift Cam, Forged High Compression Pistons, High Performance Cam Bearing, Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold and High Flow Injectors (5.5 g/sec). Stage IV Kit - 114CI to 128CI for Oil-Cooled models. Delivers increased response throughout the entire RPM range. Provides thrilling acceleration when twisting the throttle. Maintains flat torque curve from cruising RPM to redline. Can be installed without removing the engine from chassis. Retains Original Equipment Factory Warranty. 49-State U.S. EPA Compliant on '17-later Touring models.

Harley-Davidson Accessories

#92500078

£3944.54£3550.09

Member£3352.86-15%

Go big or go home. With the largest displacement of any Harley-Davidson Stage Kit, this 114CI to 131CI Stage IV Kit was designed to deliver maximum horsepower - all the way to the redline. Packaged with patent-protected cylinder technology, it allows for the largest bolt-on engine upgrade to any Milwaukee-Eight motor. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. Coupled with the kit's high-lift SE8-517 cam, high compression pistons and a 64mm throttle body and intake manifold, this combination delivers a thrilling 131 ft-lb of torque and 121 HP rear-wheel output when paired with Screamin' Eagle Street Cannon Mufflers. It's designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You'll feel the difference as soon as you twist the throttle. When installed by an authorized Harley-Davidson Dealer within 60 days of the vehicle purchase, compliant kits do not impact the vehicle's limited warranty. Kit includes CNC Ported Cylinder Head with CNC machined chamber and 1mm larger valves, Stage IV Timer Cover, SE8-517 High-Lift Cam, Forged High Compression Pistons, High Performance Cam Bearing and Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold and High Flow Injectors (5.5 g/sec). Stage IV Kit - 114CI or 117CI to 131CI for Oil Cooled models.

Harley-Davidson Accessories

#92500079

£3944.54£3550.09

Member£3352.86-15%

Go big or go home. With the largest displacement of any Harley-Davidson Stage Kit, this 114CI to 131CI Stage IV Kit was designed to deliver maximum horsepower - all the way to the redline. Packaged with patent-protected cylinder technology, it allows for the largest bolt-on engine upgrade to any Milwaukee-Eight motor. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. Coupled with the kit's high-lift SE8-517 cam, high compression pistons and a 64mm throttle body and intake manifold, this combination delivers a thrilling 131 ft-lb of torque and 121 HP rear-wheel output when paired with Screamin' Eagle Street Cannon Mufflers. It's designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You'll feel the difference as soon as you twist the throttle. When installed by an authorized Harley-Davidson Dealer within 60 days of the vehicle purchase, compliant kits do not impact the vehicle's limited warranty. Kit includes CNC Ported Cylinder Head with CNC machined chamber and 1mm larger valves, Stage IV Timer Cover, SE8-517 High-Lift Cam, Forged High Compression Pistons, High Performance Cam Bearing and Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold and High Flow Injectors (5.5 g/sec). Stage IV Kit - 114CI or 117CI to 131CI for Twin-Cooled models. Delivers increased response throughout the entire RPM range. Provides thrilling acceleration when twisting the throttle. Maintains flat torque curve from cruising RPM to redline. Can be installed without removing the engine from chassis. Retains Original Equipment Factory Warranty. 49-State U.S. EPA Compliant on '17-later Touring models.

Harley-Davidson Accessories

#92500080

£3944.54£3550.09

Member£3352.86-15%

Go big or go home. With the largest displacement of any Harley-Davidson Stage Kit, this 114CI to 131CI Stage IV Kit was designed to deliver maximum horsepower - all the way to the redline. Packaged with patent-protected cylinder technology, it allows for the largest bolt-on engine upgrade to any Milwaukee-Eight motor. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. Coupled with the kit's high-lift SE8-517 cam, high compression pistons and a 64mm throttle body and intake manifold, this combination delivers a thrilling 131 ft-lb of torque and 121 HP rear-wheel output when paired with Screamin' Eagle Street Cannon Mufflers. It's designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You'll feel the difference as soon as you twist the throttle. When installed by an authorized Harley-Davidson Dealer within 60 days of the vehicle purchase, compliant kits do not impact the vehicle's limited warranty. Kit includes CNC Ported Cylinder Head with CNC machined chamber and 1mm larger valves, Stage IV Timer Cover, SE8-517 High-Lift Cam, Forged High Compression Pistons, High Performance Cam Bearing and Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold and High Flow Injectors (5.5 g/sec). Stage IV Kit - 114CI or 117CI to 131CI for Twin-Cooled models. Delivers increased response throughout the entire RPM range. Provides thrilling acceleration when twisting the throttle. Maintains flat torque curve from cruising RPM to redline. Can be installed without removing the engine from chassis. Retains Original Equipment Factory Warranty. 49-State U.S. EPA Compliant on '17-later Touring models.

Harley-Davidson Accessories

#92500081

£3944.54£3550.09

Member£3352.86-15%

Go big or go home. With the largest displacement of any Harley-Davidson Stage Kit, this 114CI to 131CI Stage IV Kit was designed to deliver maximum horsepower - all the way to the redline. Packaged with patent-protected cylinder technology, it allows for the largest bolt-on engine upgrade to any Milwaukee-Eight motor. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. Coupled with the kit's high-lift SE8-517 cam, high compression pistons and a 64mm throttle body and intake manifold, this combination delivers a thrilling 131 ft-lb of torque and 121 HP rear-wheel output when paired with Screamin' Eagle Street Cannon Mufflers. It's designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You'll feel the difference as soon as you twist the throttle. When installed by an authorized Harley-Davidson Dealer within 60 days of the vehicle purchase, compliant kits do not impact the vehicle's limited warranty. Kit includes CNC Ported Cylinder Head with CNC machined chamber and 1mm larger valves, Stage IV Timer Cover, SE8-517 High-Lift Cam, Forged High Compression Pistons, High Performance Cam Bearing and Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold and High Flow Injectors (5.5 g/sec). Stage IV Kit - 114CI or 117CI to 131CI for Oil Cooled models. Delivers increased response throughout the entire RPM range. Provides thrilling acceleration when twisting the throttle. Maintains flat torque curve from cruising RPM to redline. Can be installed without removing the engine from chassis. Retains Original Equipment Factory Warranty. 49-State U.S. EPA Compliant on '17-later Touring models.

Harley-Davidson Accessories

#92500082

£3944.54£3550.09

Member£3352.86-15%

Go big or go home. With the largest displacement of any Harley-Davidson Stage Kit, this 107CI to 128CI Stage IV Kit is designed to deliver maximum horsepower - all the way to the redline. Packaged with patent-protected cylinder technology, it allows for the largest bolt-on engine upgrade to any Milwaukee-Eight motor. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. It's designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You'll feel the difference as soon as you twist the throttle. Delivers increased response throughout the entire RPM range. Provides thrilling acceleration when twisting the throttle. Maintains flat torque curve from cruising RPM to redline. Can be installed without removing the engine from chassis. Includes CNC Ported Cylinder Head with CNC machined chamber and 1mm larger valves, 128 Stage IV Timer cover, SE8-517 High-Lift Cam, Forged High Compression Pistons. Also includes High Performance Cam Bearing and High Performance Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold, High Flow Injectors (5.5 g/sec). Pending 49-State U.S. EPA compliant.

Harley-Davidson Accessories

#92500094

£3779.28£3401.35

Member£3212.39-15%

Go big or go home. With the largest displacement of any Harley-Davidson Stage Kit, this 107CI to 128CI Stage IV Kit is designed to deliver maximum horsepower - all the way to the redline. Packaged with patent-protected cylinder technology, it allows for the largest bolt-on engine upgrade to any Milwaukee-Eight motor. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. Coupled with the kit's high-lift SE8-517 cam, high compression pistons and a 64mm throttle body and intake manifold, this combination delivers a thrilling 135 ft-lb of torque and 124 HP rear-wheel output when paired with Screamin' Eagle Street Cannon Mufflers for 131 kit customers. It's designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You'll feel the difference as soon as you twist the throttle. Delivers increased response throughout the entire RPM range. Provides thrilling acceleration when twisting the throttle. Maintains flat torque curve from cruising RPM to redline. Can be installed without removing the engine from chassis. Includes CNC Ported Cylinder Head with CNC machined chamber and 1mm larger valves, 131 Stage IV Timer cover, SE8-517 High-Lift Cam, Forged High Compression Pistons. Also includes High Performance Cam Bearing and High Performance Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold, High Flow Injectors (5.5 g/sec). Pending 49-State U.S. EPA compliant.

Harley-Davidson Accessories

#92500095

£3779.28£3401.35

Member£3212.39-15%

This Stage IV Kit was developed to deliver maximum horsepower from the Milwaukee-Eight engine - all the way to the redline. The system-matched combination of larger displacement cylinders, free flowing CNC-Ported cylinder heads and a cam with the highest available valve lift are the starting point to building the perfect engine for the performance junkie.

Harley-Davidson Accessories

#92500062

£3045.94£2741.35

Member£2589.05-15%

This Stage IV Kit was developed to deliver maximum horsepower from the Milwaukee-Eight engine - all the way to the redline. The system-matched combination of larger displacement cylinders, free flowing CNC-Ported cylinder heads and a cam with the highest available valve lift are the starting point to building the perfect engine for the performance junkie. Designed for a high level of flexibility, this package is ideal for riders who like to comfortably cruise at lower rpm but still have plenty of arm-pulling acceleration when you whack the throttle. Kit includes CNC Ported Cylinder Heads with Performance Valve Springs, 64mm Throttle Body, High Flow Injectors (5.5g/s), 4.075" Bolt-On Cylinders, Forged 11:1 High Compression Aluminum Coated Pistons and Rings, SE8-515 Cam, Cam Bearing Upgrade, High Performance Tappets, Multi-layer Coated Head Gaskets, High Capacity Clutch Springs (1200N) and most necessary gaskets and seals. Increases power by up to 40% when compared to the Original Equipment engine configurations. Delivers increased response throughout the entire RPM range. Maintains flat torque curve from cruising RPM to redline. Can be installed without removing the engine from the chassis. Retains Original Equipment Factory Warranty. 50-State U.S. EPA compliant. Includes Screamin' Eagle Cylinder Heads with Performance Valve Springs, Throttle Body, High Flow Injectors, Bolt-On Cylinders, Pistons, Piston Rings, Cam, Cam Bearings, Tappets, Head Gaskets, Top End, Cylinder Base and Cam Cover Gaskets, and Clutch Springs.

Harley-Davidson Accessories

#92500073

£3045.94£2741.35

Member£2589.05-15%

If you're looking to build a fast, track-ready 103, this kit eliminates the guess work. Kit includes CNC-Ported Factory Cylinder Heads with high performance valve springs, matching high-compression forged aluminum 10.5:1 pistons, SE-259E cams for higher lift for a given duration, Perfect-Fit Pushrods to accommodate the higher cam lift, and a 58mm throttle body with High Flow Injectors to feed the beast. Kits for Twin Cam 96 models include Big Bore cylinders, and the Twin Cam 103 kit uses the Original Equipment 103 cylinders. The kit also includes high-performance clutch spring and sprocket retention hardware to put the power to the ground. Kit includes top end gaskets.

Harley-Davidson Accessories

#27516-08F

£2903.40£2613.06

Member£2467.89-15%

If you're looking to build a fast, track-ready 103, this kit eliminates the guess work. Kit includes CNC-Ported Factory Cylinder Heads with high performance valve springs, matching high-compression forged aluminum 10.5:1 pistons, SE-259E cams for higher lift for a given duration, Perfect-Fit Pushrods to accommodate the higher cam lift, and a 58mm throttle body with High Flow Injectors to feed the beast. Kits for Twin Cam 96 models include Big Bore cylinders, and the Twin Cam 103 kit uses the Original Equipment 103 cylinders. The kit also includes high-performance clutch spring and sprocket retention hardware to put the power to the ground. Kit includes top end gaskets.

Harley-Davidson Accessories

#27517-08E

£2903.40£2613.06

Member£2467.89-15%

If you're looking to build a fast, track-ready 103, this kit eliminates the guess work. Kit includes CNC-Ported Factory Cylinder Heads with high performance valve springs, matching high-compression forged aluminum 10.5:1 pistons, SE-259E cams for higher lift for a given duration, Perfect-Fit Pushrods to accommodate the higher cam lift, and a 58mm throttle body with High Flow Injectors to feed the beast. Kits for Twin Cam 96 models include Big Bore cylinders, and the Twin Cam 103 kit uses the Original Equipment 103 cylinders. The kit also includes high-performance clutch spring and sprocket retention hardware to put the power to the ground. Kit includes top end gaskets.

Harley-Davidson Accessories

#92500018A

£2714.87£2443.38

Member£2307.64-15%

Build a fast, reliable 110 cubic inch Twin Cam hauler without having to remove the motor from the chassis. This Stage III Street Performance Kit combines system-matched Screamin' Eagle big bore cylinders, high compression pistons and performance cams and valve train components with the Original Equipment cylinder heads for a cost-effective boost in torque and performance.

Harley-Davidson Accessories

#92500035

£2087.41£1878.67

Member£1774.30-15%

This Stage III kit has been developed to deliver the kind of real-world power increase Touring riders will feel each time they roll on the throttle. The bump up in displacement and compression paired with a Screamin' Eagle SE8-511 camshaft deliver a significant increase in torque and power over stock and may restore the sensation of riding solo when you're loaded down with a passenger and gear. Black Highlighted. Delivers up to 31% more horsepower and 18% more torque compared to the Original Equipment engine configuration. This street-compliant performance kit has been designed and tested as a system by the performance experts at Harley-Davidson. Includes 4.155" Big Bore Bolt-On Cylinders, Forged 10.9:1 High Compression Pistons and Rings, SE8-511 Camshaft, High Capacity Tappets, Stage III Timer Cover Medallion. Includes Multi-Layer Coated Head Gaskets, Cylinder Base and Cam Cover Gaskets, most necessary gaskets and seals. Pending 49-State U.S. EPA compliant. Race only.

Harley-Davidson Accessories

#92500139

£2065.73£1859.16

Member£1755.87-15%

This Stage III kit has been developed for the rider looking for a solid seat of the pants increase you can feel every time you roll on the throttle. The bump up in displacement and compression deliver a significant increase in torque and power over stock, all the while restoring the sensation of riding solo when you're loaded down. Delivers up to 23% more torque and increases power by up to 17% when compared to the Original Equipment 114CI engine configuration. Delivers increased throttle response throughout the entire RPM range. Produces flexible roll-on passing power without a required downshift. Delivers excellent stop-light to freeway speed on-ramp acceleration. Retains Original Equipment Factory Warranty. Includes 4.155" Big Bore Bolt-On Cylinders, Forged 11.0:1 High Compression Pistons and Rings, SE8-447 Torque Cam, High Capacity Tappets, High Performance Cam Bearing, Stage III Timer Cover & Insert. Includes Multi-Layer Coated Head Gaskets, Cylinder Base and Cam Cover Gaskets, most necessary gaskets and seals. Pending 49-State U.S. EPA compliant.

Harley-Davidson Accessories

#92500084

£2031.64£1828.48

Member£1726.89-15%

This Stage III kit has been developed for the rider looking for a solid seat of the pants increase you can feel every time you roll on the throttle. The bump up in displacement and compression deliver a significant increase in torque and power over stock, all the while restoring the sensation of riding solo when you're loaded down. Delivers up to 13% more torque and increases power by up to 15% when compared to the Original Equipment 114CI engine configuration. Delivers increased throttle response throughout the entire RPM range. Produces flexible roll-on passing power without a required downshift. Delivers excellent stop-light to freeway speed on-ramp acceleration. Retains Original Equipment Factory Warranty. Includes 4.155" Big Bore Bolt-On Cylinders, Forged 11.0:1 High Compression Pistons and Rings, SE8-447 Torque Cam, High Capacity Tappets, High Performance Cam Bearing, Stage III Timer Cover & Insert. Includes Multi-Layer Coated Head Gaskets, Cylinder Base and Cam Cover Gaskets, most necessary gaskets and seals. Pending 49-State U.S. EPA compliant.

Harley-Davidson Accessories

#92500086

£2031.64£1828.48

Member£1726.89-15%

This Center-Cooled generation of Extreme Ported Cylinder Heads has been meticulously designed to optimize air/fuel flow and velocity. Building on the previous Oil/Twin-Cooled generation of CNC-Ported Milwaukee-Eight Cylinder Heads, the Screamin' Eagle team refined the intake and exhaust ports based on extensive racing experience to maximize the flow of high-velocity air through 2mm larger (42mm intake/34mm exhaust) valves than the Original Equipment heads, and fully machined the combustion chamber to optimize combustion efficiency. Due to the new race-inspired intake port geometry, these cylinder heads require the use of either the Screamin' Eagle High-Flow 68mm Intake Manifold (P/N 27300218) or the Screamin' Eagle Extreme Flow 68mm CNC Ported Intake Manifold (P/N 27300217). Factory equipped with high-performance valve springs that remain stable with high-lift cams and in high-RPM operation. For race use only.

Harley-Davidson Accessories

#16501332

£1976.83£1779.15

Member£1680.31-15%

This Center-Cooled generation of Extreme Ported Cylinder Heads has been meticulously designed to help optimize air/fuel flow and velocity. Building on the previous Oil/Twin-Cooled generation of CNC-Ported Milwaukee-Eight Cylinder Heads, the Screamin' Eagle team refined the intake and exhaust ports based on extensive racing efforts to help maximize the flow of high-velocity air through 2mm larger (42mm intake/34mm exhaust) valves than the Original Equipment heads and fully machined the combustion chamber to help optimize combustion efficiency. Due to the new race-inspired intake port geometry, these heads require the use of either the Screamin' Eagle High-Flow 68MM Intake Manifold (P/N 27300218) or the Screamin' Eagle Extreme Flow 68MM CNC Ported Intake Manifold (P/N 27300217). Factory equipped with high-performance valve springs that remain stable with high-lift cams and in high-RPM operation.

Harley-Davidson Accessories

#16501333

£1976.83£1779.15

Member£1680.31-15%

These Stroker flywheels provide 103 or 113 cubic inches of raw power for your Twin Cam engine, by increasing your stock stroke from 4.0" to 4-3/8" and adding the appropriate pistons and cylinders. The flywheels and rods are made from high-strength forgings. The assembly makes use of the Original Equipment (straight press) crankpin and bearings, which mean you get proven durability.

Harley-Davidson Accessories

#23600-00A

£1813.88£1632.49

Member£1541.80-15%

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.

Harley-Davidson Accessories

#16925-11

£1673.23£1505.91

Member£1422.25-15%

This Center-Cooled generation of Extreme Ported Cylinder Heads has been meticulously designed to help optimize air/fuel flow and velocity. Building on the previous Oil/Twin-Cooled generation of CNC-Ported Milwaukee-Eight Cylinder Heads, the Screamin' Eagle team refined the intake and exhaust ports based on extensive racing efforts to help maximize the flow of high-velocity air through 2mm larger (42mm intake/34mm exhaust) valves than the Original Equipment heads and fully machined the combustion chamber to help optimize combustion efficiency. Due to the new race-inspired intake port geometry, these heads require the use of either the Screamin' Eagle High-Flow 68MM Intake Manifold (P/N 27300218) or the Screamin' Eagle Extreme Flow 68MM CNC Ported Intake Manifold (P/N 27300217). Factory equipped with high-performance valve springs that remain stable with high-lift cams and in high-RPM operation. Race-only.

Harley-Davidson Accessories

#16501060

£1652.57£1487.31

Member£1404.68-15%

Designed in conjunction with the system-matched components of the Screamin' Eagle Milwaukee-Eight Stage IV Performance Kit, these CNC-Ported Cylinder Heads have been meticulously machined to optimize air/fuel flow and velocity. Starting with a unique Screamin' Eagle cylinder head casting, the Screamin' Eagle team has dedicated countless hours of computer simulation and flow bench testing to maximize the flow through the intake and exhaust ports. Black highlighted. Factory equipped with high performance valve springs that remain stable with high lift cams and in high RPM operation. Ports are meticulously machined on a five axis CNC machine to increase the velocity of the intake charge and to maximize exhaust scavenging. When combined with a larger bore throttle body, the cylinder heads provide improved efficiency of cylinder filling, leading to more explosive power and increased rear wheel torque when compared to stock.

Harley-Davidson Accessories

#16500379

£1579.24£1421.32

Member£1342.35-15%

Designed in conjunction with the system-matched components of the Screamin' Eagle Milwaukee-Eight Stage IV Performance Kit, these CNC-Ported Cylinder Heads have been meticulously machined to optimize air/fuel flow and velocity. Starting with a unique Screamin' Eagle cylinder head casting, the Screamin' Eagle team has dedicated countless hours of computer simulation and flow bench testing to maximize the flow through the intake and exhaust ports. Black highlighted. Factory equipped with high performance valve springs that remain stable with high lift cams and in high RPM operation. Ports are meticulously machined on a five axis CNC machine to increase the velocity of the intake charge and to maximize exhaust scavenging. When combined with a larger bore throttle body, the cylinder heads provide improved efficiency of cylinder filling, leading to more explosive power and increased rear wheel torque when compared to stock.

Harley-Davidson Accessories

#16500512

£1579.24£1421.32

Member£1342.35-15%

Designed in conjunction with the system-matched components of the Screamin' Eagle Milwaukee-Eight Stage IV Performance Kit, these CNC-Ported Cylinder Heads have been meticulously machined to optimize air/fuel flow and velocity. Starting with a unique Screamin' Eagle cylinder head casting, the Screamin' Eagle team has dedicated countless hours of computer simulation and flow bench testing to maximize the flow through the intake and exhaust ports. Black granite highlighted. Factory equipped with high performance valve springs that remain stable with high lift cams and in high RPM operation. Ports are meticulously machined on a five axis CNC machine to increase the velocity of the intake charge and to maximize exhaust scavenging. When combined with a larger bore throttle body, the cylinder heads provide improved efficiency of cylinder filling, leading to more explosive power and increased rear wheel torque when compared to stock.

Harley-Davidson Accessories

#16500527

£1579.24£1421.32

Member£1342.35-15%

Designed in conjunction with the system-matched components of the Screamin' Eagle Milwaukee-Eight Stage IV Performance Kit, these CNC-Ported Cylinder Heads have been meticulously machined to optimize air/fuel flow and velocity. Starting with a unique Screamin' Eagle cylinder head casting, the Screamin' Eagle team has dedicated countless hours of computer simulation and flow bench testing to maximize the flow through the intake and exhaust ports. The ports are meticulously machined on a five axis CNC machine to increase the velocity of the intake charge and to maximize exhaust scavenging. When combined with a larger bore throttle body, these CNC Cylinder Heads provide improved efficiency of cylinder filling, leading to more explosive power and increased rear wheel torque when compared to stock. The CNC Ported Heads are factory equipped with high performance valve springs that remain stable with high lift cams and in high RPM operation.

Harley-Davidson Accessories

#16500538

£1579.24£1421.32

Member£1342.35-15%

Designed as part of the 128CI and 131CI Screamin' Eagle Milwaukee-Eight Stage IV Performance Kit, this Second Generation of Extreme Ported Cylinder Heads has been meticulously designed to optimize air/fuel flow and velocity. Improving on the First Generation of CNC-Ported Milwaukee-Eight Cylinder Heads, the Screamin' Eagle team refined the intake and exhaust ports to maximize the flow of high-velocity air through the 1mm larger valves of 128CI and 131CI engines and fully machined the combustion chamber to optimize combustion efficiency. Replacement cylinder heads for Air/Oil-Cooled '17-later Milwaukee-Eight models equipped with 128 or 131CI Stage IV kits.

Harley-Davidson Accessories

#16500750

£1579.24£1421.32

Member£1342.35-15%

This 4-3/8" stroker flywheel assembly can be combined with 3-7/8" cylinders and pistons to produce 1690cc (103") displacement, 4.00" cylinders and pistons for 1800cc (110"), or with 4.060" cylinders and pistons for 1856cc (113") displacement.

Harley-Davidson Accessories

#23727-07A

£1424.50£1282.05

Member£1210.83-15%

This 4-3/8" stroker flywheel assembly can be combined with 3-7/8" cylinders and pistons to produce 1690cc (103") displacement, 4.00" cylinders and pistons for 1800cc (110"), or with 4.060" cylinders and pistons for 1856cc (113") displacement. All EFI models require ECM calibration (priced separately). For race application only.

Harley-Davidson Accessories

#23728-07A

£1424.50£1282.05

Member£1210.83-15%

Make your Iron 883 roar. This complete conversion kit will alter the personality of your 883-equipped Sportster model. Designed to bring your XL883 model up to XL1200 specifications, this kit includes Sportster Stage I Air Cleaner Kit, XL1200 Cylinder Heads, and XL1200 Cylinders and Pistons. Kit includes cylinders and cylinder heads. Black Highlighted.

Harley-Davidson Accessories

#29784-07

£1355.10£1219.59

Member£1151.84-15%

Make your Iron 883 roar. This complete conversion kit will alter the personality of your 883-equipped Sportster model.

Harley-Davidson Accessories

#30003-10

£1355.10£1219.59

Member£1151.84-15%

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.

Harley-Davidson Accessories

#92500039

£1350.96£1215.86

Member£1148.32-15%

Increase the displacement of your Milwaukee-Eight engine without removing the engine from the chassis. The Screamin' Eagle product team has engineered a patent-protected 4.31" Big Bore Cylinder that increases the internal bore but slips into the existing case bore without modification. Black highlighted.

Harley-Davidson Accessories

#16800407

£1291.06£1161.95

Member£1097.40-15%

CNC Ported Heads offer a cost-effective approach to upgrading the performance of your motorcycle. The intake and exhaust ports are meticulously machined for smooth surfaces, improving the flow characteristics of air and fuel in order to provide enhanced performance. But it doesn't end there: the proven stock valves rest in reshaped valve seats to further improve flow rates. The combustion chambers have been machined for smooth surfaces and feature a blended radius on the bathtub edge to reduce detonation by eliminating hot spots and promoting improved combustion. The head gasket surface has been milled to maintain stock combustion chamber volume (59.9cc), which results in stock compression when used with Original Equipment pistons. Compression can be increased with the installation of Screamin' Eagle high-compression pistons. Heads are assembled with Original Equipment valves and high-performance valve springs that support cams with lift up to.585". All EFI models require ECM calibration (priced separately). For race application only.

Harley-Davidson Accessories

#16500074

£1017.35£915.62

Member£864.75-15%

Increase the displacement of your Milwaukee-Eight engine without removing the engine from the chassis. The Screamin' Eagle product team has engineered a patent-protected 4.155" Big Bore Cylinder that increases the internal bore but slips into the existing case bore without modification. When combined with the appropriate piston and flywheel combination in the Screamin' Eagle Stage IV kits, these cylinders can increase the displacement of your Milwaukee-Eight engine from 107CI to 119CI or from 114CI and 117CI to 122CI. Replacement cylinders for '17-later Milwaukee-Eight models equipped with Screamin' Eagle 119 or 122CI Stage III kits. Kit includes front and rear cylinders and gaskets.

Harley-Davidson Accessories

#16800332

£904.76£814.28

Member£769.05-15%

This kit was developed for the budget minded rider that wants to experience crisp throttle response and acceleration they can feel at slower speeds. The 5% increase in torque can be felt immediately off the line and continues to build by up to a 14% increase @ 4500 RPM - the ideal power band for passing slow moving vehicles. Delivers enhanced torque and horsepower in the low to mid RPM range. Produces passing power without a downshift or high revs. Minimally invasive, only requiring opening of the cam chest. Retains Original Equipment Factory Warranty. Includes Gloss Black covers. Stage II Upgrade.

Harley-Davidson Accessories

#92500074A

£557.71£501.94

Member£474.05-15%

This kit was developed for the budget minded rider who wants to experience an adrenalin-pumping burst of speed on the way to the red line. The additional power starts to build at 3000 RPM and increases by up to 24% at the red line. When riding aggressively, you must downshift to lower gears to keep the engine in the higher RPM range. Ideal for riders looking for excitement and willing to ride in the upper RPM range. Produces greater acceleration in the mid and upper RPM range. Minimally invasive, requiring only the opening of the cam chest. Retains Original Equipment Factory Warranty. Includes covers in gloss black. Stage II Upgrade.

Harley-Davidson Accessories

#92500075A

£557.71£501.94

Member£474.05-15%

This kit was developed for the budget minded rider that wants to experience crisp throttle response and acceleration they can feel at slower speeds. The 5% increase in torque can be felt immediately off the line and continues to build by up to a 14% increase @ 4500 RPM - the ideal power band for passing slow moving vehicles. Delivers enhanced torque and horsepower in the low to mid RPM range. Produces passing power without a downshift or high revs. Minimally invasive, only requiring opening of the cam chest. Retains Original Equipment Factory Warranty. 50-State U.S. EPA compliant.

Harley-Davidson Accessories

#92500047A

£526.72£474.05

Member£447.71-15%

This kit was developed for the budget minded rider that wants to experience that adrenalin-pumping burst of speed while heading toward the red line. The additional power starts to build @ 3000 RPM and continues to build by up to 24% at redline. Riding the bike aggressively will require downshifting to lower gears to keep the engine operating in the higher RPM range. Ideal for riders looking for excitement and are willing to ride in the upper RPM range. Produces greater acceleration in the mid and upper RPM range. Minimally invasive, only requiring opening of the cam chest. Retains Original Equipment Factory Warranty. 50-State U.S. EPA compliant.

Harley-Davidson Accessories

#92500058A

£526.72£474.05

Member£447.71-15%

4.060" Standard Bore. Forged from high-strength aluminum, these 10.5 to 1 ratio pistons feature nickel-plated surfaces for enhanced durability, and a special Teflon coating for improved wear-resistance required for racing applications. These pistons include Titanium SST rings to withstand the stresses seen in racing. Complete kit includes pistons, rings, wrist pins, and clips.

Harley-Davidson Accessories

#22574-10

£435.83£392.25

Member£370.46-15%

These pistons were developed specifically for the Screamin' Eagle Milwaukee-Eight 119CI and 122CI Stage III kits. They increase the compression of the engine and, in combination with these kits, provide an impressive increase in torque and power. Replacement pistons for '17-later Milwaukee-Eight models equipped with Screamin' Eagle 107CI to 119CI Stage III kits. Forged from high-strength aluminum. Precision-manufactured with coated skirts for a tightly toleranced fit and quieter operation. The complete set includes two pistons, rings, wrist pins and clips.

Harley-Davidson Accessories

#21900129

£429.62£386.66

Member£365.18-15%