Home / Engine Stuff / Air-Tech Rotax Gear Box Clutch / Clutch, Assembled Clutch, Assembled$664.00 Air-Tech Rotax Gear Box Clutch Clutch, Assembled quantity Add to cart SKU: RK400C Category: Air-Tech Rotax Gear Box Clutch Description Description The primary purpose of the clutch is to disengage the prop from the engine allowing it to start and operate at idle without vibration. When the engine is idling (below 2350 RPM) the prop is not turning. Installation of the clutch replaces the gear box flywheel and the hardy disk. Added weight is approx. 3 Lbs. At this time the clutch is only available in the “C” gearbox.