STM Evoluzione Wet Slipper Clutch For Buell XB9 / XB12 and Harley Davidson Sportster 883 /1200

Evoluzione Slipper Clutch

The Infamous Evoluzione Slipper Clutch has been used for more than 20 years in racing and now you can get it too!

The clutch uses the cornerstone of STM technology, the 'Ball & Ramp' actuation for smooth slipper clutch operation along with another STM exclusive .. 'FLS', Forced Lubrication System. The STM 'FLS' increases the amount of engine oil flowing through the wet clutch, which leads to cooler running temperatures and cleaner conditions thus increasing the performance and longevity of the clutch components.

STM offers the only adjustable slipper clutch on the market

The STM slipper clutch brings innovative performance improvements to the street market through the controlled engine braking system (CEB)

Highly effective engine to clutch-to-rear wheel power management system decreases unwanted engine braking and rear wheel drag when braking hard for a corner

Prevents damage to the engine and gearbox by reducing the mechanical stress caused by the back-torque of the engine and avoiding any chance of over-revving

Provides better clutch feel and smoother action

Uses original friction plates, drive plates, and basket

NOTE: Tool UTL-0030 is Required to Properly Torque this clutch

How the springs work:

The primary and secondary springs are mounted in such a way as to guarantee a preload which generates an initial resilient spring force.

How the primary spring works:

When the lever is actuated, the preloading position of the primary spring is varied and reduced. The spring returns an elastic force of contrast to the action of the lever.

How the secondary spring works:

The torque generated by the rear wheel tends to raise the drum. The secondary spring is compressed with respect to the initial resting position and generates an elastic contrast force.

All STM clutches and parts are machined and assembled in-house at the STM facility located in Chieri, Italy. Constructed from the highest grade raw materials - CNC machined to the tightest tolerances and hard coated to ensure product longevity.

STM clutches have the ability to be adjusted (tuned) to riders' needs through the use of different weight primary and secondary clutch springs.