Big Bore Kits

Burly Brand - Black Brawler Kit fits M8 Softail Models Features: Designed to grind down during impacts to prevent bike from catching and flipping Functions as a highway bar for a secure grip and comfortable footrest on long rides Durable materials...

S&S Cycle - 136" Big Bore Cylinder Kit fits '17 & Up M8 Engines S&S Cycle's Big Bore Cylinder & Piston Kit delivers a mighty bore increase (4.320") that, in turn, delivers a huge power increase! It is compatible with stock crankcases,...

S&S Cycle - Black Powdercoat 95" Big Bore Kit fits '99-'06 Twin Cam Engines (3.875" Bore, 4" Stroke, 9.7:1 Comp. W/ Stock Heads) This Big Bore Kit produces outstanding outcomes with stock cylinder heads. It comes complete with cylinders, pistons,...

S&S Cycle - Silver Powdercoat 95" Big Bore Kit fits '99-'06 Twin Cam Engines (3.875" Bore, 4" Stroke, 9.7:1 Comp. W/ Stock Heads) This Big Bore Kit produces outstanding outcomes with stock cylinder heads. It comes complete with cylinders, pistons,...

S&S Cycle - Stone Gray Powdercoat 117" Big Bore Kit fits '07-'17 Twin Cam Engines (4.125" Bore, 4⅜" Stroke, 10.5:1 Comp. W/ Stock Heads) This Big Bore Kit produces outstanding outcomes with stock cylinder heads. It comes complete with cylinders,...

S&S Cycle - Black Powdercoat 117" Big Bore Kit fits '07-'17 Twin Cam Engines (4.125" Bore, 4⅜" Stroke, 10.5:1 Comp. W/ Stock Heads) This Big Bore Kit produces outstanding outcomes with stock cylinder heads. It comes complete with cylinders, pistons,...

S&S Cycle - Stone Gray Powdercoat 124" Big Bore Kit fits '07-'17 Twin Cam Engines (4.125" Bore, 4⅝" Stroke, 11.4:1 Comp. W/ Stock Heads) This Big Bore Kit comes complete with cylinders, pistons, rings and gaskets (head, base and exhaust)...

S&S Cycle - 3⅝" Big Bore Cylinder & Big Bore Piston Kit fits '66-'84 Shovelhead Engines This kit can be used to construct an 88" engine, or to replace the cylinders and piston in an engine with an existing S&S® stock bore stroker kit...

S&S Cycle - Silver 100" Bolt-In Sidewinder® 4" Big Bore Kit fits '99-'06 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 which will...

S&S Cycle - Wrinkle Black 100" Bolt-In Sidewinder® 4" Big Bore Kit fits '99-'06 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 - Silver 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 which will...

S&S Cycle - Wrinkle Black 124" Big Bore Kit W/ 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 - Wrinke Black 128" Big Bore Kit W/O 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 - Black Granite 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 - Black/Highlighted 4.375" Stroke 129" Big Bore Cylinder & Piston Kit fits '17 & Up M8 Engines  S&S Cycle's Big Bore Cylinder & Piston Kit delivers a mighty bore increase (4.320") that, in turn, delivers a huge power...

S&S Cycle - Black 4.375" Stroke 129" Big Bore Cylinder & Piston Kit fits '17 & Up M8 Engines S&S Cycle's Big Bore Cylinder & Piston Kit delivers a mighty bore increase (4.320") that, in turn, delivers a huge power increase! It is...

S&S Cycle - Black 4.5" Stroke 132" Big Bore Cylinder & Piston Kit fits '17 & Up M8 Engines S&S Cycle's Big Bore Cylinder & Piston Kit delivers a mighty bore increase (4.320") that, in turn, delivers a huge power increase! It is...

S&S Cycle - Silver 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 are...

S&S Cycle - 100" Power Packages fits '99-'06 Twin Cam Engines (Exc. '06 Dynas) S&S Cycle has created the largest big-bore kits available today, without doing crankcase mods! This kit increases displacement to 100" ('99-'06) and the cylinders fit...

S&S Cycle - 128" Power Packages fits '17-'20 M8 Water/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...

V-Twin - 107" Big Bore Twin Cam Cylinder Kit fits '99-'06 FLST/FXST/FLT/FXD Model 107" Twin Cam big bore cylinder kit includes 10.5:1 piston kit and steel cylinders with black finish. Requires case machining and fits a 4" stroke flywheel...

S&S Cycle - 310-1055A - 124" Power Package - Gear 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 - Black/Highlighted 4.5" Stroke 132" Big Bore Cylinder & Piston Kit fits '17 & Up M8 Engines  S&S Cycle's Big Bore Cylinder & Piston Kit delivers a mighty bore increase (4.320") that, in turn, delivers a huge power...