S&S Cycle 4.320" Bore Cylinder Kit Black Granite - Harley Milwaukee-Eight 2017-Up

$1,643.95
PICK MY V-TWIN MOTORCYCLEThis part is vehicle specific. Pick your motorcycle to confirm it fits.
OUT OF STOCK

Specifications

BRANDS&S Cycle
TYPEPiston Sets - Powersports
SKUT14-852171
PART NUMBER910-0850A
DISPLACEMENT136 cubic inches
BORE4.320 inches
FINISHBlack Granite powder coat
INCLUDEDMLS head gaskets
WEIGHT29.75 lb

Fitment

Fits these motorcycles

Listed per manufacturer fitment data. Not sure? Email us and we confirm before you order.

REVIEWS (8)

The S&S Cycle 4.320" Bore Cylinder Kit in Black Granite is a complete top-end package that raises displacement to 136 cubic inches. With a 4.320-inch bore, it is built to deliver a meaningful increase in engine capacity for riders looking to add power and torque from their V-twin.

Riders choose this kit because it works with stock crankcases and requires no machining, which keeps the installation straightforward. It retains the stock engine height, so the upgrade does not change how the top end sits in the engine. Designed to match the factory look, the kit has a powder coat finish in Black Granite.

The kit includes MLS head gaskets for a secure seal. It is designed for use with S&S 4 5/8-inch stroker cranks, giving riders a clear path to a larger, more capable engine without extensive custom fabrication.

For off-road / closed-course race use only.

Specifications

  • Brand: S&S Cycle
  • Part Number: 910-0850A
  • Displacement: 136 cubic inches
  • Bore: 4.320 inches
  • Finish: Black Granite powder coat
  • Included: MLS head gaskets
  • Weight: 29.75 lb

Common questions

What displacement does this cylinder kit provide?

The kit provides 136 cubic inches of displacement with a 4.320-inch bore.

Does this kit require machining to the crankcases?

No, the kit works with stock crankcases and does not require machine work.

What finish does the kit have and what is included?

The kit has a Black Granite powder coat finish and includes MLS head gaskets.

CUSTOMER REVIEWS
4.9
8 CUSTOMER REVIEWS
Sep 26, 2019

Really nice kit great directions for install and ring gap. Follow the directions and you can't go wrong..

— Anonymous
Apr 26, 2022

Excellent service and pricing im very satisfied

— Anonymous
Sep 26, 2019

Better than OEM.. can't go wrong.

— Anonymous
Mar 30, 2026

Very happy with this kit

Simple, easy kit.

— Joe G
Mar 29, 2026

SMS makes great aftermarket upgrades

— Ron B
Oct 24, 2025

👍👍 For fast delivery

Parts came just like as expected. They look great! Can't wait to install these bad boys along with a few other parts.

— Bruce H