S&S CYCLE 128" Power Package for 114"/117" Oil Cooled M8 —4.25" bore, 4.5" stroke – 18-26 Softail, 19-26 Touring, 22-23 CVO, 20-25 Trike

Upgrade your oil‑cooled M‑Eight with a complete bolt‑on big‑bore power package that increases 114\"/117\" engines to 128\". 🔧🇺🇸 This kit is designed for enthusiasts who want reliable, proven performance without case machining.

• Big bore bolt‑on kit increases 114\"/117\" with 4‑1/2\" stroke M‑Eight to 128\" with no case machining required
• 4‑1/4\" bore cylinders with 11:1 forged pistons for strong, consistent combustion
• S&S oil pump/cam plate with blue anodized finish; passage plugs are removable for servicing
• Independent scavenge sections for flywheel cavity and camchest with debris screens and a magnet in the camchest
• Increased oil flow capacity on both the oil feed and scavenge side; adjustable pressure relief valve serviceable with unit installed
• Quikee pushrods with chrome pushrod tubes; S&S premium tappets and hard‑anodized billet tappet cuffs for improved stability at high lift and rpm
• S&S 550 cam optimized for big‑bore applications and high‑performance conical single‑wire valve springs rated up to .605\" lift
• All necessary gaskets, bearings and hardware for bolt‑on installation are included

Designed and manufactured for durability and serviceability, this performance kit delivers increased displacement and oiling improvements while retaining straightforward installation for experienced technicians.