Softail Big Bore Kits

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 - 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 - 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 - 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...

Burly Brand - Black Brawler Kit fits M8 Softail Model 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...

Motorshop - KB 107" Twin Cam Forged Piston Set fits '99-'06 FLST/FXST/FLT/FXD Model Forged piston set has a compression ratio of 10.5:1 and is for a stock stroke. Set includes rings, circlips and pins. Note: Run engine at moderate speeds for at...

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 - 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 - 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 - 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 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 - 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 - 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/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...

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 - 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 - 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 - 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 - 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 - 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 - 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 - 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...

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...