S&S has been building big bore kits since the 60s and has it down to an absolute science. Our latest efforts are aimed at the Milwaukee Eight platform (2017 and newer big twins) and open up a whole new level of performance for these engines. Combining a new design forged piston with their 4.25" cylinders to net a tire melting 131 cubic inches when paired with their 4.625" stroker crank. We build our big bore kits and cranks to much tighter tolerarances and with higher quality materials than the factory parts. This new piston/cylinder kit will be a solid platform for massive power.
Must be used with our stroker flywheels to achieve 131" displacement (part #s 320-0605, 320-0620)
S&S Cycle 2017+ M8 Models 4.250in Bore 4-5/8in Stroke Cylinder Kit - Wrinkle Black w/ Highlight
Powder coat finish match factory finish, giving the bike a "sleeper" advantage
Huge displacement increase means huge power increase
.030" MLS (multi-layered steel) head gaskets
Original engine serial numbers are retained
131" Kit, Wrinkle Black with Fin Highlights
Includes 131" Cam Cover Badge
Works with stock crankcases
Retains stock engine height
