128" Power Package Engine Performance Kit — 4.250" bore, 4.500" stroke, 11.1:1

S&S CYCLE 128" Power Package Engine Performance Kit — 4.250" bore, 4.500" stroke, 11.1:1 – 21-23 Trike, 19-23 Touring, 17, 23 CVO

S&S CYCLE
0904-0072
310-1108A
Bolt-on big-bore performance kit that increases displacement with forged pistons, S&S 550 cams, enhanced oiling and all gaskets and hardware for installation. Made in the U.S.A.
Hurry! only 9 items left in stock.
€2,328.25
€3,128.03
Save €799.78
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  Delivery policy

In stock items will be shipped within 1-3 days.

  Return policy

You can return the products within 14 days for a full refund, check our returns policy.

🔥 The 128" Power Package Engine Performance Kit is a bolt-on big-bore solution designed to upgrade M-Eight engines with no case machining required. Ideal for riders seeking more displacement and higher rpm stability, this kit combines forged internals, premium cam components, and enhanced oiling for reliable performance.

  • Big-bore bolt-on kit increases displacement using a longer stroke without case machining required
  • 4-1/4" bore cylinders with 11:1 forged pistons for increased strength and compression
  • S&S oil pump and cam plate finished in blue anodize; removable passage plugs for easy servicing
  • Independent scavenge sections for the flywheel cavity and cam chest with debris screens and a magnet in the cam chest to reduce contamination
  • Increased oil flow capacity on both feed and scavenge sides, plus an adjustable pressure relief valve serviceable with the unit installed
  • Quickee pushrods with chrome tubes, S&S premium tappets and hard-anodized billet tappet cuffs to improve stability at high lift and rpm
  • S&S 550 cams optimized for big-bore applications and S&S valve springs compatible with up to .605" lift
  • High-performance conical single-wire spring design and all necessary gaskets, bearings, and hardware for bolt-on installation
  • Made in the U.S.A. 🇺🇸

⚙️ This complete kit focuses on real-world serviceability: removable plugs, easily adjustable relief valve, and independent scavenge sections simplify maintenance. It’s engineered for robust performance and longevity under demanding conditions.

: 0904-0072
In Stock

Data sheet

Type
Engine
Units
Kit
Color/Finish
Highlighted Fins, Black Granite
Base Color
Black
Style
Big Bore
Brand
S&S CYCLE
Bore Size
4,250"
Displacement
128"
Stroke Length
4,500"
Compression Ratio
11.1:1
Cam Drive Type
Gear

Shipping Policy

Shipping Areas:

We ship to:

  • Spain (Peninsula and Balearic Islands)
  • European Union countries

We do not ship to the Canary Islands, Ceuta, or Melilla.

Shipping Times:

  • Spain (Peninsula): 2–4 business days
  • Balearic Islands: 3–5 business days
  • EU countries: 3–7 business days depending on destination

Shipping Costs:

Shipping costs are calculated automatically at checkout based on destination and weight.

Free shipping may be offered for qualifying orders, as specified on our website.

Order Processing:

Orders are processed within 1–2 business days after payment confirmation. Orders placed on weekends or public holidays are processed the next business day.

Delivery Issues:

If your order is delayed or arrives damaged, you must notify us within 14 calendar days. We will investigate the issue and offer a resolution in accordance with applicable consumer protection laws.

Return & Withdrawal Policy

Right of Withdrawal:

In accordance with Royal Legislative Decree 1/2007 (Ley de Defensa de los Consumidores y Usuarios), you have the right to withdraw from your purchase within 14 calendar days from the date of receipt, without giving any reason.

To exercise this right, contact us via email or through our website, providing your order number and contact details.

Return Conditions:

  • Products must be unused, in original condition and packaging.
  • Return shipping costs are the responsibility of the customer, unless the product is defective or sent in error.
  • Refunds will be issued within 14 days of receiving the returned goods.

Items Excluded from Return:

  • Custom or personalized products
  • Sealed items that were unsealed after delivery and are unsuitable for return due to hygiene (e.g. cosmetics, personal care)
  • Digital content delivered electronically once download or streaming has begun

If you want to return an item, please contact us first to give you detailed instructions.

This product fits the following vehicles. Use the filters below to narrow down the list if needed.

Manufacturer Model Family Year Notes
Harley Davidson Tri Glide Ultra 114 Trike 2021
Harley Davidson Tri Glide Ultra 114 Trike 2022
Harley Davidson Tri Glide Ultra 114 Trike 2023
Harley Davidson Ultra Limited Shrine Edition 114 Touring 2021
Harley Davidson Ultra Limited Shrine Edition 114 Touring 2022
Harley Davidson Ultra Limited Shrine Edition 114 Touring 2023
Harley Davidson Ultra Limited Shrine Edition 114 Touring 2019 Gear Drive
Harley Davidson Ultra Limited Shrine Edition 114 Touring 2020 Gear Drive
Harley Davidson Ultra Limited Low 114 Touring 2019 Gear Drive
Harley Davidson Electra Glide Ultra Limited CVO 114 CVO 2017 Gear Drive
Harley Davidson Street Glide CVO 114 CVO 2017 Gear Drive
Harley Davidson Road Glide Limited 114 Touring 2021
Harley Davidson Road Glide Limited 114 Touring 2022
Harley Davidson Road Glide Limited 114 Touring 2023
Harley Davidson Road Glide Limited 114 Touring 2020 Gear Drive
Harley Davidson Road Glide Limited Anniversary CVO 117 CVO 2023
Harley Davidson Road Glide Ultra 114 Touring 2019 Gear Drive