Use on 40274-08 compensator kits. Replaces 37810-08A sprocket retainer. Prevents compensator sprocket assembly from working itself loose. Peace of mind is key when it comes to building a high performance powertrain. The Compensating Sprocket Lock Kit is now ready and available for select Harley-Davidson motorcycles. This system positively secures the compensating sprocket so it cannot come loose. Rubber mounted engines may insulate the rider and frame mounted components from vibration; but the entire powertrain; including the compensating sprocket; is still at risk from fasteners coming loose due to shaking. Additionally; today’s larger and more powerful engines can cause a lesser fastening system to come loose from large power pulses combined with the back and forth motion from getting on and off the throttle. Along with drive line security; the JIMS Compensating Sprocket Lock Kit keeps the alternator rotor in place to prevent damage to the charging system as well. This is not only a race engine item; stock bikes will also benefit from this upgrade to increase reliability and safety. Not for early style compensator with spring cup attached to rotor or 2014 stock compensator.