Big Bore Kits

S&S Cycle - 128" Power Packages fits '17-'20 M8 Oil-Cooled Engines This Power Package increases your 114"/117" with a 4-1/2" stroke M8 to 128". It is available in a wrinkle black or black granite finish and your choice of cylinders with or without...

S&S Cycle - Wrinkle Black 124" Big Bore Kit W/O Highlighted Cylinder Fins fits '17-'21 107" M8 Engines This is a bolt-on kit that features the biggest bore possible with no machining of the crankcases necessary! It includes all of the required...

S&S Cycle - Wrinkle Black XL883 to 1200 Conversion Kit fits '86-'20 XL 883 Models This conversion kit installs in no time at all since the pistons are already fit to the cylinders, making them prepared for assembly as soon as you open them! The kits...

S&S Cycle - 124" Power Packages fits '17-'20 M8 Oil-Cooled Engines This bolt-on Power Package increases your 107" M8 Engine to 124". It comes in a wrinkle black finish and is available with or without fin highlighting. You can also choose between a...

S&S Cycle - Hooligan Kits fits '00-'20 XL Models S&S Cycle's Hooligan Kits are bolt on big-bore kits that provide easy installation without any machining or rebalancing. The cams are .482" lift and 240° duration intake and 234° degree...

S&S Big Bore Kit for M8 Harley Softail & Touring '17-Up This S&S Big Bore Kit is for Milwaukee-Eight Harley Softail and Touring models 2017 and up, including Softail Heritage Classic and Breakout. Available as a whole kit or as a cylinder...

S&S Cycle - 96" Big Bore Kit fits '84-'00 Evolution Big Twin Engines (3⅝" Bore, 4⅝" Stroke, 9.75:1 Compression Ratio W/ Stock Heads) The cylinders featured in this kit are built with premium aluminum castings with cast-in iron liners. This kit also...

S&S Cycle - Wrinkle Black 110" Bolt-In Sidewinder® 4" Big Bore Kit fits '07-'17 Twin Cam Engines This Big Bore Kit has a 10.5:1 compression ratio (W/ stock 85cc heads) that will transform your engine into a street-ready and reliable machine...

S&S Cycle - Wrinke Black 128" Big Bore Kit W/ Highlighted Cylinder Fins fits '17-'20 114" 117" M8 Engines This is a bolt-on kit that features the biggest cylinder bore possible with no machining of the crankcases necessary! It includes all of the...

S&S Cycle - 110" Power Package fits '07-'17 Twin Cam Engines S&S Cycle has created the largest big-bore kits available today, without doing crankcase mods! This kit increases displacement to 110" ('07-'17) and the cylinders fit to the pistons...

S&S Cycle - 310-1050B - 124" Power Package - Chain Drive - Highlighted Fins - Chrome Pushrod Tubes - 107" M8FeaturesMade in the U.S.A.Big Bore Kit107" to 124" Big bore kitBolt on kit.No case machining requiredForged pistons11.1 Compression ratioOil...

S&S Cycle - 310-1054B - 124" Power Package - Chain Drive - Highlighted Fins - Black Pushrod Tubes - 107" M8FeaturesMade in the U.S.A.Big Bore Kit107" to 124" Big bore kitBolt on kit.No case machining requiredForged pistons11.1 Compression ratioOil...

S&S Cycle - 310-1058A - 124" Power Package - Gear Drive - Highlighted Fins - Black Pushrod Tubes - 107" M8 Features Made in the USA Big Bore Kit 107" to 124" Big bore kit Bolt on kit No case matching required Forged pistons 11:1 Compression...

S&S Cycle - 920-0100 - Big Bore Forged Piston Kit - 3.937" Bore - 107" Twin Cam - StandardFeaturesPistons are compatible with stock rods with tapered wristpin endsStock cylinders may be bored to accommodate larger pistonBore cylinders to nominal diameter...

S&S Cycle - 920-0101 - Big Bore Forged Piston Kit - 3.937" Bore - 98" Twin Cam - StandardFeaturesPistons are compatible with stock rods with tapered wristpin endsStock cylinders may be bored to accommodate larger pistonBore cylinders to nominal diameter...

S&S Cycle - 920-0071 - Piston Kit - 1250cc Big Bore - XLFeaturesPiston kit includes forged pistons, rings, wrist pin and clips for a complete motorDeck height is 1.207"Made in the USAThis kit is not compatible with XR1200 or RH Sportster.883 models...

S&S Cycle - 920-0070 - Piston Kit - 1250cc Big Bore - XLFeaturesPiston kit includes forged pistons, rings, wrist pin and clips for a complete motorDeck height is 1.207"Made in the USAThis kit is not compatible with XR1200 or RH Sportster.883 models...

S&S Cycle - 310-1227 - 129" Power Package Engine Performance Kit - Gear Drive - Oil Cooled - Highlighted Fins - M8FeaturesTransform 107" oil-cooled M8 into 129" with no case machining requiredBig bore cylinders come with matching cam, cam plate and oil...

S&S Cycle - 310-1228 - 129" Power Package Engine Performance Kit - Gear Drive - Oil Cooled - Non-Highlighted Fins - M8FeaturesTransform 107" oil-cooled M8 into 129" with no case machining requiredBig bore cylinders come with matching cam, cam plate and...

S&S Cycle - 310-1238 - 132" Power Package Engine Performance Kit - Chain Drive - Oil Cooled - Highlighted Fins - M8FeaturesTransform the 114" or the 117" oil-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in the...

S&S Cycle - 310-1232 - 132" Power Package Engine Performance Kit - Gear Drive - Oil Cooled - Highlighted Fins - M8FeaturesTransform the 114" or the 117" oil-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in the...

S&S Cycle - 310-1236 - 132" Power Package Engine Performance Kit - Gear Drive - Water Cooled - Highlighted Fins - M8FeaturesTransform the 114" or the 117" water-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in...

S&S Cycle - 310-1234 - 132" Power Package Engine Performance Kit - Gear Drive - Oil Cooled - Non-Highlighted Fins - M8FeaturesTransform the 114" or the 117" oil-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in...

S&S Cycle - 310-1230 - 132" Power Package Engine Performance Kit - Gear Drive - Water Cooled - Highlighted Fins - M8FeaturesTransform the 114" or the 117" water-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in...

S&S Cycle - 310-1224 - 129" Power Package Engine Performance Kit - Gear Drive - Oil Cooled - Highlighted Fins - M8FeaturesTransform 107" oil-cooled M8 into 129" with no case machining requiredBig bore cylinders come with matching cam, cam plate and oil...

S&S Cycle - 310-1237 - 132" Power Package Engine Performance Kit - Chain Drive - Oil Cooled - Highlighted Fins - M8FeaturesTransform the 114" or the 117" oil-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in the...

S&S Cycle - 310-1226 - 129" Power Package Engine Performance Kit - Chain Drive - Oil Cooled - Non-Highlighted Fins - M8FeaturesTransform 107" oil-cooled M8 into 129" with no case machining requiredBig bore cylinders come with matching cam, cam plate and...

S&S Cycle - 310-1231 - 132" Power Package Engine Performance Kit - Chain Drive - Oil Cooled - Highlighted Fins - M8FeaturesTransform the 114" or the 117" oil-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in the...

S&S Cycle - 310-1235 - 132" Power Package Engine Performance Kit - Chain Drive - Water Cooled - Highlighted Fins - M8FeaturesTransform the 114" or the 117" water-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in...

S&S Cycle - 310-1225 - 129" Power Package Engine Performance Kit - Chain Drive - Oil Cooled - Highlighted Fins - M8FeaturesTransform 107" oil-cooled M8 into 129" with no case machining requiredBig bore cylinders come with matching cam, cam plate and oil...

S&S Cycle - 310-1233 - 132" Power Package Engine Performance Kit - Chain Drive - Oil Cooled - Non-Highlighted Fins - M8FeaturesTransform the 114" or the 117" oil-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in...

S&S Cycle - 310-1223 - 129" Power Package Engine Performance Kit - Chain Drive - Oil Cooled - Highlighted Fins - M8FeaturesTransform 107" oil-cooled M8 into 129" with no case machining requiredBig bore cylinders come with matching cam, cam plate and oil...

S&S Cycle - 310-1229 - 132" Power Package Engine Performance Kit - Chain Drive - Water Cooled - Highlighted Fins - M8FeaturesTransform the 114" or the 117" water-cooled M8 into 132"Adjustable pressure relief valve can be adjusted with unit installed in...

S&S Cycle - 310-1107B - 128" Power Package Engine Performance Kit - Chain DriveFeaturesBig-bore bolt-on kit increases 114"/117" with 4-1/2" stroke M-Eight with no case machining required4-1/4" bore cylinders with 11:1 forged pistonsS&S oil pump/cam plate...

S&S Cycle - 310-1108A - 128" Power Package Engine Performance Kit - Gear DriveFeaturesBig-bore bolt-on kit increases 114"/117" with 4-1/2" stroke M-Eight with no case machining required4-1/4" bore cylinders with 11:1 forged pistonsS&S oil pump/cam plate...

S&S Cycle - 310-1101B - 128" Power Package Engine Performance Kit - Chain DriveFeaturesBig-bore bolt-on kit increases 114"/117" with 4-1/2" stroke M-Eight with no case machining required4-1/4" bore cylinders with 11:1 forged pistonsS&S oil pump/cam plate...

S&S Cycle - 310-1102A - 128" Power Package Engine Performance Kit - Gear Drive Features Big-bore bolt-on kit increases 114"/117" with 4-1/2" stroke M-Eight with no case machining required 4-1/4" bore cylinders with 11:1 forged pistons S&S...

S&S Cycle - 900-0354 - 106" Hot Set Up® Kit - 3.967" Bore - Wrinkle Black - Twin CamFeaturesIncreased fin area for better heat dissipationIncrease bore size from 3.750" to 3.927"4.375" stroke, 10.0:1 compression with stock headsEasy installation; no...

S&S Cycle - 91-7661 - 96" Sidewinder® - 3.625" Big Bore - Stroker Kit - Wrinkle Black - Evolution Big TwinFeaturesKit includes standard flywheel assembly, 3.625" Sidewinder® stroker big bore cylinder, 9.75:1 compression ratio pistons, rings and...

S&S Cycle - 91-7660 - 96" Sidewinder® - 3.625" Big Bore - Stroker Kit - Natural - Evolution Big TwinFeaturesKit includes standard flywheel assembly, 3.625" Sidewinder® stroker big bore cylinder, 9.75:1 compression ratio pistons, rings and gasketsFlywheel...