ZIPPERS PERFORMANCE BIG BORE KITS HARLEY GEN 2 M8 MODELS

ZIPPERS PERFORMANCE BIG BORE KITS HARLEY GEN 2 M8 MODELS 

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Increasing the size of a Milwaukee-Eight® engine is easy with Zipper’s Big Bore Cylinder Kits.  These Big Bore kits are designed for the new Gen 2 M8 engines, which have oval port heads and center cooling.

The Milwaukee-Eight® engines design is made for displacement increases and Zippers offers cylinder kits for Factory stock 4-valve head, SE heads and many Custom High Flow Heads to provide huge torque and horsepower gains.

Each of this specific bore sizes are designed to fit on the factory engine base without case boring just like like-stock installation.

4.250- 4.280 Bores

Zipper’s offers new alloy castings with bore sizes from 4.250 to 4.280

These castings are designed with additional aluminum for added strength vs a O.E. casting with a larger bore liner with the following features:
• Cast Aluminum has 1 lb. additional material for Strength and Reliability
• Stress Relieved Iron Liners
• Precision Sized on Sunnen SV-30 by Zipper’s skilled craftsman
• Special Ring Packs for Advanced Cylinder Sealing
• Gasket Surface Finish Improved for Superior Seal using Cometic MLS Gaskets
• Zipper’s Forged “Spec Built” Pistons manufactured by CP

We have many dome configurations to choose from so you can target various compression ratios. Contact Zipper’s support if you have a special requirement.

4.250 x 4.500 stroke = 128ci

Kits include precision fitted cylinders with tight tolerances, 2618 forged pistons with advanced ring packs, pins & clips, head and base gaskets and new head bolts. The rings custom sized to each cylinder.