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HARLEY-DAVIDSON Engine Kits & Rotating Assemblies
S&S Cycle 98 in. Big Bore Kits
S&S Cycle 98 in. big bore kits are a fantastic upgrade if your Harley® is just a bit tired. The thicker and beefier cylinders mean that the engine will run cooler and you'll love the forged pistons that come with the kits. These are the largest bores that can be fit in your stock engine case. The cylinder and piston kits make going to the max bore size easy. There is no machining required and stock engine height is maintained. These kits come with nearly everything needed to get the most out of the added cu. in. to your stock engine. You won't believe how much power these kits produce! Features and specifications: * Kit yields excellent results with stock cylinder heads * Easy installation—no need to bore or split existing cases, just swap the cylinders * Available in a choice of either black or silver powdercoat finish with polished fins * Increased fin area for better heat dissipation * Valve pocket recessed in S&S pistons are enlarged for oversize valves and higher lift cams
Not Yet Reviewed
$1,386.95
S&S Cycle 883 to 1200cc Hooligan Cylinder Kits
An 883 to 1200cc Hooligan cylinder kit for a Harley-Davidson®, like the ones made by S&S Cycle, provides a significant increase in engine displacement, resulting in substantially more power and torque without requiring major engine modifications, making it a popular upgrade for riders seeking better performance on their Sportster 883, with benefits like increased horsepower—by boosting the engine size from 883cc to 1200cc, the Hooligan kit delivers a noticeable power gain, allowing for better acceleration and highway cruising capabilities. Typically these kits are designed as "bolt-on" upgrades, meaning they can be installed without needing extensive machining or engine rebalancing, making the process relatively simple and straightforward. Compared to a complete engine rebuild, a Hooligan kit is a cost-effective way to significantly improve your bike's power. When installing a Hooligan kit, it may be necessary to upgrade the clutch to handle the increased torque produced by the larger engine. Depending on the specific kit and your bike setup, you may need to adjust fuel injection mapping to optimize performance.
Not Yet Reviewed
$1,128.95
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$1,822.95
S&S Cycle 124 in. Hot Set-Up Cylinder Kits
S&S Cycle 124 in. (standard compression) Hot Set-Up cylinder kits package pistons and cylinders for use as replacements or as the basis for a new engine build. The pistons are a flat dome design, and the cylinders are machined with the stock bolt pattern intended for use in stock crankcases. Select the appropriate kit for your Big Twin. S&S cylinder and piston kit contents and notes: * S&S 4 1/8 in. bore cylinders -- Durable wrinkle black powdercoat finish * Forged flat domed pistons, rings, wrist pins * Head and base gaskets * Designed for 4 5/8 in. flywheels, resulting in 124 in. displacement * Cylinders can be used with stock or S&S cylinder heads with stock bolt pattern
Not Yet Reviewed
$1,643.95
S&S Cycle 4 in. Sidewinder Big Bore Kits
Inspired by S&S Pro Stock drag race engines, S&S Cycle 4 in. Sidewinder big bore kits utilize a ductile cast iron liner wrapped in cast aluminum for optimum thermal conductivity and performance. These bolt-in kits do not require machining, re-balancing, or engine removal, and include just about everything you'll need to complete the installation. S&S Cycle 4 in. Sidewinder kits offer the biggest cylinder bore that can be installed in a stock crankcase without machining! Features: * Low-friction ductile cast iron liner * 10.5:1 compression * Bolts in with no machining, balancing, or splitting the crankcases * 88 in. engines are boosted to 100 in. * 96 in. and 103 in. engines are boosted to 110 in. * Complete kits include cylinders, pistons, gaskets, and instructions * Wrinkle black and silver cylinders that match stock finish
Not Yet Reviewed
$1,540.95
S&S Cycle 107 in. Big Bore Kits
S&S Cycle 107 in. big bore kits are easy to install and require no machining or re-balancing. These are the largest bores that can be fit in your stock engine case. This is the largest bore that can be fit in a stock engine case. Stock engine height is maintained so there are no manifold or frame fitment issues. Using an 11-fin design, the pre-finished cylinders closely resemble the OEM shape and are ready to install. Take your stock engine case as big as it'll go with S&S Cycle 107 in. big bore kits! Product features include: * CP pistons feature a 3cc pop-up dome for slightly higher compression * Cylinders feature an increased fin area for better heat dissipation * Centrifugal cast gray liner features 40,000 psi tensile strength for superior wear and performance
Not Yet Reviewed
$1,345.95
S&S Cycle M8 Big Bore Cylinders
S&S Cycle M8 big bore cylinders are bolt-on sets for Milwaukee 8 models. They are available in a Wrinkle Black finish with or without highlighted fins. Select the set you would like.
Not Yet Reviewed
$391.95
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$977.95
S&S Cycle M8 131 in. Big Bore Kits
S&S Cycle 131 in. big bore kits are aimed at the Milwaukee Eight platform for 2017 and newer big twins—and open up a whole new level of performance for these engines. When paired with an S&S 4.625 in. stroker flywheel (sold separately), engine will be a true 131cubic inches. S&S builds their big bore kits and cranks to much tighter tolerances and with higher quality materials than the factory parts. If you're the proud owner of a Harley-Davidson® Milwaukee Eight big twin and have been waiting for just the thing to boost your M8's power—the wait is over! The S&S Cycle piston/cylinder kits will be a solid platform for massive power! Features and benefits: * Huge displacement increase means huge power increase * Bolt-on kit works with stock crankcases * 4 1/4 in. bore cylinders with a new 11:1 forged piston design * Original engine serial numbers are retained * Powdercoat finish match factory finish, giving the bike a "sleeper" advantage * Includes .045 in. multi-layered steel head gaskets * Retains stock engine height * Includes 131 in. Cam Cover Badge * Available with or without highlighted fins Note: This kit must be used with S&S Cycle stroker flywheels to achieve 131 in. displacement (P/N: 320-0605, 320-0620).
Not Yet Reviewed
$1,559.95
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$1,643.95
S&S Cycle M8 124 in. Big Bore Kits
Inspired by S&S Pro Stock drag race engines, S&S Cycle 124 in. big bore kits utilize a ductile cast iron liner wrapped in cast aluminum for optimum thermal conductivity and performance. These bolt-in kits do not require machining, re-balancing or engine removal, and include just about everything you'll need to complete the installation. S&S Cycle 124 in. big bore kits are available in wrinkle black or wrinkle black with highlighted finned cylinders. Transform your stock engine into a 124 in. monster with the installation of a 124 in. big bore kit from S&S Cycle! S&S Cycle 124 in. big bore kit features: * Available for 107 M8 models * 107 to 124 in. big bore kit * Bolt-on kit * Includes gaskets and hardware required for installation * 4.250 in. bore * Forged Pistons * 11:1 compression ratio
Not Yet Reviewed
$1,561.95
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$1,643.95
S&S Cycle 1200cc to 1250cc Hooligan Cylinder Kits
Whether you are looking for better acceleration for everyday riding or more power for spirited driving, S&S Cycle 1200cc to 1250cc Hooligan cylinder kits provide a noticeable improvement. The larger displacement from 1200cc to 1250cc directly translates to more power, making the bike faster and more responsive, especially noticeable in acceleration and mid-range torque. These kits are designed to be "bolt-on" meaning they can be installed without needing to machine the engine cases or rebalance the crankshaft, making the upgrade process fairly straightforward. Each kit is tailored with the necessary components for your specific HD® model. Most Hooligan kits utilize the existing stock heads, pushrods, and fuel system, minimizing the need for additional parts or adjustments. Compared to a full engine rebuild or custom build, S&S Cycle's Hooligan kits are a relatively affordable way to significantly improve performance. Select the kit designed for your application needs.
Not Yet Reviewed
$1,822.95
S&S Cycle M8 Flywheel Assemblies
Crankshafts are the heart of any performance engine. S&S Cycle M8 flywheel assemblies are stronger, more durable, and trued to a spec others can only dream of. These cranks for the Milwaukee-Eight platform are the best of the best to build your high performance engine around. Available in different strokes with tapered rods or full wrist pin rods, select the M8 flywheel assembly needed for your motorcycle's engine. Features and benefits: * Available in 4 3/8, 4 1/2, and 4 5/8 in. stroke * Comes with balance gear installed for easier installation * Heat-treated 4140 material is harder and more than twice as strong as stock * Stronger assembly eliminates need to weld crankpin * S&S high-strength forged connecting rods are designed with Finite Element Analysis to eliminate weak spots and handle more power * Full width connecting rods have more material to handle higher stress * Perfect for gear drive camshafts * Consistent balance and precision machining * Capable of higher rpm--more available power
Not Yet Reviewed
$1,995.95
S&S Cycle 89 in. Stock Bore Cylinder Kits
S&S Cycle offers 89 in. stock bore cylinder kits for various Harley-Davidson® motorcycles, allowing for easy upgrades on a variety of models. One of the key advantages of using one of these S&S Cycle cylinder kits is that they use the stock cylinder bore, and often requires minimal machining or crankcase splitting, making installation relatively straightforward compared to larger big bore kits. There are several benefits of using one of these to upgrade your bike's performance, including increased engine displacement without major modifications to the stock engine, maintaining the original look, cost-effectiveness compared to full big bore kits, and often requiring minimal machining or crankcase splitting for installation. Even with a relatively small displacement increase to 89 cubic inches, the engine will experience a noticeable power boost compared to the stock configuration. To optimize performance, consider upgrading other engine components like pistons, cams, and exhaust systems alongside this S&S Cycle stock bore cylinder kit. Select the kit specifically designed for your Harley® model and year.
Not Yet Reviewed
$1,282.95
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$1,441.95
S&S Cycle 124 in. Big Bore/Stroker Hot Set-Up Kits
The S&S Cycle 124 in. big bore/stroker Hot Set-Up kits transform a stock Harley-Davidson® engine into a 124 in. monster. It includes: 4 1/8 in. bore pistons; big bore cylinders finished in wrinkle black powdercoat; a dynamically balanced 4 5/8 in. stroke 3-piece flywheel assembly complete with heavy-duty connecting rods and integral mainshafts; 640 gear drive Easy Start camshafts; chromoly steel adjustable pushrods; premium tappets; and Super Stock 91cc cylinder heads. When installed, the kits yield a 124 in. engine with a compression ratio of 11:1. Although the engine is .960 in. taller than stock, there are no frame clearance problems—and a stock EFI throttle body will fit, because the manifold mounting surfaces of the heads have been specially machined to fit a stock length manifold. If you ride a 2006 HD Dyna model, or a balanced or non-balanced Big Twin from 2007-17, these top-end engine rebuild kits are for you. Note: No fuel or ignition system is included. However, for the best results, a larger EFI throttle body, performance intake, and performance exhaust are recommended. The EFI system must be recalibrated. Although not mandatory, S&S recommends adding an oil cooler to bikes ridden in warmer climates. S&S does not recommend compression ratios higher than 10:1 for Tri Glide or other 3-wheel models (including conversions) due to extra loads caused by the lugging nature of these bikes. Detonation and subsequent engine damage may result.
Not Yet Reviewed
$7,104.95
S&S Cycle 124 in. Power Packages with Gear Drive Cam
S&S Cycle 124 in. power packages with gear drive cam are the ideal combination of performance and savings to transform a Harley-Davidson® motorcycle without breaking the bank. Each kit is tailored with the necessary components for your specific HD® model. These kits offer significant benefits, including a substantial increase in horsepower and torque across the powerband, improved throttle response, better cam timing accuracy due to the gear drive mechanism, and a more reliable valve train compared to a standard chain-driven cam, making it ideal for riders seeking a powerful and responsive engine upgrade, especially on larger displacement bikes like the Milwaukee-Eight models. Installing a 124 in. power package often necessitates additional tuning adjustments, including adjusting fuel delivery and ignition timing to optimize performance. Select the power package with gear drive cam designed specifically for your HD® model and engine to ensure proper fitment.
Not Yet Reviewed
$3,460.95
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$3,695.95
S&S Cycle M8 High Compression 132/136 in. Big Bore Kits
S&S Cycle M8 high-compression 132/136 in. Big Bore kits are high performance engine upgrades for 2017+ Harley-Davidson® Milwaukee-Eight engines, designed to maximize displacement without boring the engine case. They offer significant torque and horsepower gains using 4.320 in. bore cylinders, with the 132 in. kit designed for stock stroke, while 136 in. requires a stroker flywheel. Key details: * Performance: Drastically boosts horsepower and torque, offering a "thrilling" ride with improved throttle response * No case machining: Engineered to fit stock crankcases, avoiding expensive and time-consuming case boring * Components: Includes 4.320 in. bore cylinders, premium forged pistons, and gaskets * Compatibility: Fits 2017–25 Touring models and 2018–25 Softails * Factory appearance: Powdercoated finish matches stock engine finishes * 132 in. vs 136 in.: The 132 in. kit operates with the stock 4.5 in. stroke, while the 136 in. kit requires a 4.625 in. stroker flywheel to achieve maximum displacement. * These kits are intended for performance-oriented riders looking for a "bang for buck" upgrade, often requiring supporting modifications like high-flow exhaust, air cleaners, and dyno tuning to achieve best results.
Not Yet Reviewed
$1,849.95
S&S Cycle V111 Cylinder Kits
The S&S Cycle V111 cylinder kits are an exceptional choice for riders who choose to re-work their bikes for more power. This 4 1/8 in. bore cylinder and piston kit by S&S Cycle replaces the cylinders and pistons on early production S&S V111 engines for 1984-1999 Big Twins. With top-of-the-line components, the V111 cylinder kits include S&S 4 1/8 in. bore cylinders, forged pistons, rings, wrist pins, head and base gaskets. Pistons are flat topped design intended for use with S&S Super Stock cylinder heads. The cylinders are machined with the S&S bolt pattern and are intended for use in S&S crankcases used in early S&S V111 engines. Designed for 4 3/8 in. stroke flywheels, resulting in 111 in. displacement. For best performance expectations, appropriate camshafts, performance air cleaner, performance exhaust and fuel system tuning are required.
Not Yet Reviewed
$1,571.95
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$1,702.95
S&S Cycle 117 in. Big Bore Kits
S&S Cycle 117 in. big bore kits are a popular choice for riders looking to upgrade their engine power without major modifications. Available for a variety of Harley-Davidson® motorcycles, each kit is tailored with the necessary components for your specific HD® model. Many kits come with a powdercoat finish that can match the stock engine look to maintain a clean aesthetic. Using one of S&S Cycle's big bore kits can provide significant benefits like a noticeable increase in horsepower and torque due to the larger engine displacement, relatively easy installation with minimal machine work required, a quality build with durable components, and a good balance of performance and reliability. For best performance, appropriate camshafts, performance air cleaner, performance exhaust and fuel system tuning are required. Although not mandatory, S&S Cycle recommends adding an oil cooler to bikes ridden in warmer climates. Select the S&S Cycle big bore kit designed for your application needs.
Not Yet Reviewed
$1,643.95
S&S Cycle 106 in. Big Bore Hot Set-Up Kits
S&S Cycle 106 in. Big Bore Hot Set-Up cylinder kits are easy to install. No machining or rebalancing is required, and the engine does not need to be removed from the chassis. With these kits, the resulting 106 in. engine has a compression ratio of 10:1, is stock height (no frame clearance problems), and a stock EFI throttle body will fit. Kits include: * 3.927 in. bore pistons, rings, wrist pins * Big bore cylinders finished in silver or wrinkle black powder coat * 585C chain drive Easy Start camshafts * Chromoly steel adjustable pushrods * High performance tappets * Gaskets
Not Yet Reviewed
$2,143.95
S&S Cycle 129 in. Power Packages with Chain Drive Cam
S&S Cycle offers 129 in. power packages with chain drive cam for a variety of Harley-Davidson© street bikes from 2017 and up. These packages are the ideal combination of performance and savings designed to transform your engine from mild to wild. They combine S&S's biggest big bore cylinders with matched 550 cam/cam-plate/oil pump and everything else a high performance cam chest needs to make big, reliable horsepower. Transform your 107 in. into a 129 in. monster. Additional details: * Available with 129 in. Big Bore pistons/cylinders * 550 lift cam for the perfect combination of horsepower and torque * Works with stock crankcases * Powdercoat finish matched to factory * MLS (multi-layered steel) head gaskets * Includes tappets, tappet cuffs, and high lift springs * Includes 129 cam cover badge
Not Yet Reviewed
$3,359.95
S&S Cycle M8 129 in. Big Bore Kits
The S&S Cycle M8 129 in. Big Bore kits are a high performance engine upgrade for Harley-Davidson Milwaukee-Eight 107 in. engines, designed to increase displacement to 129 cu. in. They are bolt-on kits that require no crankcase machining or engine removal, featuring a 4.32 in. bore, 11:1 compression ratio, and forged pistons. Available with highlighted or non-highlighted cylinders. Key details: * Massive performance increase: Transforms the 107 in. engine into a high-torque 129 in. powerplant * Bolt-on installation: Installs without boring the engine cases, saving machine work costs * Retains stock components: Fits with stock heads, flywheels, and retains stock engine height * Durability: Features aluminum cylinders with cast iron sleeves for better durability * Pump gas compatible: Despite the high compression (11:1), it is designed for pump gas * Wrinkle black powdercoat finish to match factory engines. Kit contents: * 4.32 in. Big Bore cylinders * Forged pistons with rings * MLS (Multi-Layered Steel) head gaskets * Includes cam cover badge
Not Yet Reviewed
$1,643.95
S&S Cycle T124 Cylinder Kits
The T124 cylinder kits from S&S Cycle are an exceptional choice for riders who choose to re-work their bikes for more power. This 4 1/8 in. bore cylinder and piston kit replaces the cylinders and pistons on early production S&S T124 engines for 1999-2006 Big Twins. The T124 cylinder kits include top-of-the-line components: S&S 4 1/8 in. bore cylinders, forged pistons, rings, wrist pins, head and base gaskets. Pistons are flat topped design intended for use with S&S Super Stock cylinder heads. The cylinders are machined with the S&S bolt pattern and are intended for use in S&S crankcases used in early S&S T124 engines. Designed for 4 3/8 in. stroke flywheels, resulting in 124 in. displacement. For best performance expectations, appropriate camshafts, performance air cleaner, performance exhaust and fuel system tuning are required.
Not Yet Reviewed
$1,635.95
S&S Cycle 128 in. Power Packages with Gear Drive Cam
S&S Cycle offers 128 in. power packages with gear drive cam for a variety of Harley-Davidson© street bikes from 2017 and up. Kit details include: BIG BORE KIT: * 4.250 in. bore * Forged pistons * 11.1:1 compression ratio OIL PUMP/CAM PLATE: * Precision-machined from billet aluminum * Passage plugs removable for servicing * Independent scavenge sections for flywheel cavity and cam chest * Debris screens in both scavenge pickups * Magnet in cam chest to help stop debris from entering oil pump * Increased flow capacity on both feed and scavenge side * Pressure relief valve is adjustable with unit installed in engine * Kits now include updated oil pump with groove for optional OEM oil seal PUSHRODS: * Quickee pushrods with chrome covers TAPPETS: * Hand-assembled to exacting tolerances * Reduced valvetrain noise from start-up to shut-down * Close tolerances for low leak-down rates * Fast pump-up and superior high-RPM performance TAPPET CUFFS: * Hard anodized black coating * Billet aluminum construction * Stronger than stock material eliminates distortion * Improve tappet stability in high lift and high RPM situations CAM: * S&S 550 cam—designed for big bore applications * Gear drive kits provide improved cam timing accuracy and eliminate stock chain tensioner * Gear drive kits include outer drive gears VALVE SPRINGS: * Work well with cams up to .605 lift * High performance conical single-wire spring * Includes top collars, keepers, and valve seals/bottom collars
Not Yet Reviewed
$3,427.95
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$3,460.95
S&S Cycle Flywheel Assemblies
Why put your bike engine back together with stock parts—when you can upgrade with one of the S&S Cycle flywheel assemblies? These 3-piece units are forged and heat-treated from 4140 steel, making them harder and stronger than stock. They're precision-machined to be truer (for less vibration), and are assembled with integral mainshafts and lightweight connecting rod forgings. Stock flywheels shift out of true under heavy loads; improve your motorcycle with an S&S Cycle flywheel assembly.
Not Yet Reviewed
$1,695.95
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$1,794.95
S&S Cycle 80 in. Stock Bore Cylinder Kits
The S&S Cycle 80 in. stock bore cylinder kits for a Harley-Davidson® offers the benefit of maintaining the original engine characteristics while providing a reliable and readily available replacement option. Unlike "big bore" kits which enlarge the cylinder diameter to increase engine displacement and horsepower, a stock bore kit simply replaces worn cylinders with new ones of the same size. These stock bore cylinder kits are ideal for situations where you need to rebuild the engine without significantly altering its power delivery or overall performance, while still achieving a quality repair. If your Harley® engine needs a rebuild due to wear and tear, the S&S Cycle 80 in. stock bore cylinder kits are a good choice to restore the engine to its original functionality. Select the S&S Cycle big bore kit specifically designed for your HD® model and year.
Not Yet Reviewed
$1,155.95
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$1,995.95
S&S Cycle 132 in. Power Packages with Chain Drive Cam
S&S Cycle offers 132 in. power packages with chain drive cam for a variety of Harley-Davidson© street bikes from 2017 and up. These packages are the ideal combination of performance and savings designed to transform your engine from mild to wild. They combine S&S's biggest big bore cylinders with matched 550 cam/cam-plate/oil pump and everything else a high performance cam chest needs to make big, reliable horsepower. Additional details: * Available with 132 in. Big Bore pistons/cylinders * 550 lift cam for the perfect combination of horsepower and torque * Works with stock crankcases * Powdercoat finish matched to factory * MLS (multi-layered steel) head gaskets * Includes tappets, tappet cuffs, and high lift springs * Includes 132 cam cover badge * 132 Power Pack: Stock heads, 550 cam, stealth AC, stock throttle body, S&S manifold, power tune duals, MK45 muffler * Recommended for closed course competition racing
Not Yet Reviewed
$3,359.95
