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S&S Cycle M8 129 in. Big Bore Kits

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The S&S Cycle M8 129 in. Big Bore kits are a high performance engine upgrade for Harley-Davidson Milwaukee-Eight 107 in. engines, designed to increase displacement

The S&S Cycle M8 129 in. Big Bore kits are a high performance engine upgrade for Harley-Davidson Milwaukee-Eight 107 in. engines, designed to increase displacement to 129 cu. in. They are bolt-on kits that require no crankcase machining or engine removal, featuring a 4.32 in. bore, 11:1 compression ratio, and forged pistons. Available with highlighted or non-highlighted cylinders.

Key details:

* Massive performance increase: Transforms the 107 in. engine into a high-torque 129 in. powerplant
* Bolt-on installation: Installs without boring the engine cases, saving machine work costs
* Retains stock components

The S&S Cycle M8 129 in. Big Bore kits are a high performance engine upgrade for Harley-Davidson Milwaukee-Eight 107 in. engines, designed to increase displacement to 129 cu. in. They are bolt-on kits that require no crankcase machining or engine removal, featuring a 4.32 in. bore, 11:1 compression ratio, and forged pistons. Available with highlighted or non-highlighted cylinders.

Key details:

* Massive performance increase: Transforms the 107 in. engine into a high-torque 129 in. powerplant
* Bolt-on installation: Installs without boring the engine cases, saving machine work costs
* Retains stock components: Fits with stock heads, flywheels, and retains stock engine height
* Durability: Features aluminum cylinders with cast iron sleeves for better durability
* Pump gas compatible: Despite the high compression (11:1), it is designed for pump gas
* Wrinkle black powdercoat finish to match factory engines.

Kit contents:

* 4.32 in. Big Bore cylinders
* Forged pistons with rings
* MLS (Multi-Layered Steel) head gaskets
* Includes cam cover badge