Roll Ace Street Lockup Clutch — What It Is & When Do You Need It
A lockup clutch is commonly used in racing applications to increase clutch holding power as engine RPM rises. It uses L‑shaped lockup arms that convert centrifugal force from the spinning clutch into additional clamping force on the pressure plate. As RPM increases, the lockup arms apply more force.
Traditional drag‑race lockup clutches often use six arms and require a modified pressure plate with hardened steel inserts. These systems provide extremely high clamping force and fine adjustability—ideal for turbocharged bikes that experience a large mid‑range torque spike as boost comes on.
Why the Roll Ace Street Lockup Is Different
We designed the Roll Ace Street Lockup specifically for those wanting to Roll race their supercharged Kawasaki H2. It uses three lockup arms, which we found to be the ideal balance of added clamping force and smooth, predictable lever feel for street use. While you can still fine‑tune the system by adding or removing arm weights, the unit is intended to be a set‑and‑forget upgrade.
The lockup contains three hardened steel buttons that the arms press against. These buttons transfer force to the pressure plate while minimizing wear on the clutch components.
Perfect Match for Supercharged Applications
Superchargers produce boost in direct proportion to engine RPM, meaning power increases linearly as revs rise. A lockup clutch mirrors this behavior, clamping force increases with RPM. As the engine makes more power, the clutch automatically applies more pressure to keep everything locked together.
Lighter Lever Feel, Stronger Grip
Because the lockup provides additional clamping force at higher RPM, extra heavy clutch springs are no longer required. You get a lighter, more comfortable clutch lever feel while still maintaining the ability to hold high horsepower.
Fitment Requirements
The lockup assembly is taller than the OEM clutch, so it must be used with our CNC‑machined billet quick‑access clutch cover. This upgrade kit includes:
- A taller “top hat” window section with new O‑ring
- The lockup plate with pre‑weighted arms
- Three hardened steel buttons
Options
- See‑through window: A polycarbonate (Lexan) window allows you to watch the clutch operate. It is extremely strong, heat‑resistant, and replaceable.
- Solid top hat: For riders who prefer not to show off their clutch.
- Custom anodizing: Available for the top hat (additional lead time required).
- Lockup colour options: Multiple anodized colours available—see dropdown for choices.
Compatibility
Available for all H2 clutches, both 3‑spring and 6‑spring versions.
Note: On H2SX and H2SXSE models, the radiator header tank must be relocated to clear the taller top hat.
