S&S CYCLE 128" Power Package Engine Performance Kit — 4.5" stroke, 4.25" bore, 11.1:1 – 21-23 Trike, 19-23 Touring, 17, 23 CVO

Upgrade your M-Eight with a bolt-on big-bore performance kit that increases displacement without case machining, delivering aggressive power and street-friendly drivability. ⚙️

The kit pairs forged pistons with precision cylinders and includes an S&S oil pump and cam plate finished in blue anodize, plus removable passage plugs for straightforward servicing.

• Independent scavenge sections for the flywheel cavity and cam chest enhance oil control
• Debris screens in both scavenge pickups and a magnet in the cam chest help protect the oil pump
• Increased oil flow capacity on feed and scavenge sides, and an adjustable pressure relief valve tunable while installed
• Quickee pushrods with chrome tubes, S&S premium tappets, and hard-anodized billet aluminum tappet cuffs for improved stability at high lift and rpm
• S&S 550 cams and high-performance conical single-wire valve springs designed for big-bore use
• Complete with all necessary gaskets, bearings, and hardware for bolt-on installation

Made in the U.S.A. Not recommended for Tri-Glide or other three-wheel models, including conversions, due to the lugging nature of those bikes. 🔧