S&S Cycle 2007+ BT 4.250in Bore 4.840in - Wrinkle Black w/o Highlight

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)

Powder coat finish match factory finish, giving the bike a "sleeper" advantage

S&S Cycle 2007+ BT 4.250in Bore 4.840in - Wrinkle Black w/o Highlight

Huge displacement increase means huge power increase

131" Kit, Wrinkle Black without Fin Highlights

.030" MLS (multi-layered steel) head gaskets

Original engine serial numbers are retained

Includes 131" Cam Cover Badge

Works with stock crankcases

Retains stock engine height