TUNED WITH PURPOSE.

4CS_Fork.jpg

4CS


PERFORMANCE CONVERSION



*DISCONTINUED - Rebuild services available for existing conversions only.

included

  • Revalve and Rebuild (Labor).

  • Kreft Compression Adjusters.

  • Kreft Base Valve Pistons.

  • Kreft Rev2 Mid-Valve Pistons.

  • Kreft Bottoming Control System.

  • Upper Cartridge Bleed and Check Plug.

  • Lower Cartridge Bleed Plug.

not included

  • Springs.

  • Wear items like seals, bushings, and fluid.

fitment

KTM:

  • 2015 - 2016 SX / SX-F

  • 2014 - 2016 XC / XC-F / SIX-DAYS EDITION

Husqvarna:

  • 2014 - 2016 TC / FC/ TE / FE

additional options

service PRICING

$150 USD

Note: cost of wear parts and fluid not included // not available for DIY installation.

*DISCONTINUED - Rebuild services available for existing conversions only.

 

Technical Overview

the 4cs solution

Kreft Moto’s 4CS Performance Conversion reinvents the 4CS fork. Using our system of high performance parts and internal modifications, combined with a genuine custom valving setting for each individual rider, we turn this troubled fork into the star performer in the WP lineup.

4cs base valves

Our 4CS base valve pistons use compression port geometry optimized for the 4CS fork’s low-displacement 8mm damper rod. This design provides improved sensitivity to sharp bumps and increased bottoming resistance. They are machined from solid steel and ground for perfect flatness across the shim sealing surface.

Kreft Moto bottoming control system

The 4CS Bottoming Control System provides a hydraulic cushion in the last 60mm of fork travel. It increases bottoming resistance exponentially with fork velocity - so full travel is available at slower speeds, but hydraulic force ramps up quickly when bottoming is imminent. In addition to improved bottoming resistance, this system also allows us to specify lower oil heights and more compliant compression damping for maximum plushness without bottoming.

 
 

4cs compression adjusters

Kreft Moto’s 4CS compression adjusters install at the bottom of the fork, providing much-needed adjustable fluid flow at the base valve (the OEM fork has no adjustment at the base valve). This allows us to disable WP’s problematic check-controlled bleed system, and make both the compression and rebound adjustments to work properly. Our flow control design is unlike anything else available for 4CS - and it shows when you ride the fork.

rev2 midvalves

The Rev2 mid valve piston uses a twin-port design for maximum compression port area and natural shim bending motion. A custom rectangular rebound shim provides a larger port inlet without increasing overall piston height. A Teflon-coated steel piston band minimizes friction.

cartridge bleed plugs

The 4CS fork has large fixed bleed holes in the fork cartridge. This design provides very little damping control for low-speed movements, and necessitates the use of compensating factors to keep the fork up in the stroke. Those compensating factors make the fork harsh. Our system works by carefully controlling oil flow at low speeds, creating a hydraulic cushion to support the fork in motion. We use special inserts to close off the factory bleed orificies at both the upper and lower parts of the cartridge, allowing the compression adjuster to do its job.