S&s Cycle 128" M8 Big Bore Performance Kit
S&s Cycle 128" M8 Big Bore Performance Kit
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Estimated delivery: Feb 05 - Feb 09
About this product
About this product
Unleash the full potential of your Milwaukee-Eight engine with the S&S Cycle 128" Power Package Engine Performance Kit. This comprehensive kit transforms your 114" or 117" M8 into a fire-breathing 128 cubic inch powerhouse, delivering significant gains in horsepower and torque.
Description
The S&S 128" Big Bore Kit is engineered for bolt-on performance, requiring no case machining for installation on 4.5" stroke M8 engines. At the heart of the kit are 4.25" bore cylinders paired with high-compression 11:1 forged pistons, maximizing combustion efficiency and power output. The kit includes the renowned S&S oil pump and cam plate, featuring a blue anodized finish for enhanced durability and style. This advanced oiling system boasts independent scavenge sections for the flywheel cavity and cam chest, ensuring optimal lubrication and reduced oil temperatures. Debris screens and a magnetic pickup further protect the oil pump from contaminants, contributing to long-term reliability.
Performance enhancements continue with Quickee pushrods, chrome pushrod tubes, and S&S premium tappets, complemented by hard-anodized, black-coated tappet cuffs for superior tappet stability in high-lift, high-rpm conditions. The S&S 550 cams, designed specifically for big bore applications, work in harmony with S&S valve springs to optimize valve train dynamics. All necessary gaskets, bearings, and hardware are included for a seamless bolt-on installation. This kit is proudly made in the U.S.A., ensuring top-quality craftsmanship and performance. Experience the ultimate in M8 engine performance with the S&S 128" Power Package.
Features & highlights
- Big bore kit boosts engine displacement to 128 cubic inches.
- No case machining required for 4.5" stroke M8 engines.
- High-compression 11:1 forged pistons for maximum power.
- S&S oil pump and cam plate with advanced oil scavenging.
- S&S 550 cams optimized for big bore performance.
- Includes all necessary gaskets and hardware for easy installation.
- Made in the U.S.A.
Technical specifications
- Brand: S&S Cycle
- Displacement: 128"
- Bore Size: 4.250"
- Stroke Length: 4.500"
- Compression Ratio: 11.1:1
- Cam Drive Type: Gear
- Cooling System: Oil Cooled, Water Cooled
- Type: Engine Kit
- Color/Finish: Highlighted Fins, Black Granite
Important to know
This kit is designed for use with Milwaukee-Eight engines that have a 4.5" stroke. Professional installation is recommended to ensure optimal performance and reliability.
Shipping & Return
Shipping & Return
Free shipping to GLS parcel shop parcel box for purchases over DKK 1,000.
GLS home delivery costs DKK 59.
We do our best to ship your order as quickly as possible. All orders are generally packed within 24 hours on weekdays.
There is a 14-day return policy. Read more
Parts Denmark Info
Parts Denmark Info
Parts Denmark is a new webshop based in Denmark. We have a physical location you can visit (No showroom yet), and we have both email and phone support in our opening hours.
Our company info is:
Parts Denmark ApS
VAT: DK45974758
Dam Holme 11
3660 Stenløse, Denmark
hello@partsdenmark.com
+45 222 333 29
Best regards,
William Svendsen & Martin Høyer (Owners)
Specifications
S&S CYCLE
310-1108A
Performance Kit
4,250"
11,1:1
128"
4,500"
Gear
Engine
Black
Kit
Oil Cooled, Water Cooled


Who is behind Parts Denmark
Martin and William are the duo behind Parts Denmark — an unlikely but awesome combo of a tech-savvy young IT wizard and a seasoned motorcycle guru who’s seen (and fixed) it all. Together, we’ve built a team with big ambitions, plenty of passion, and a shared mission to create great things — side-by-side with you.

