The most effective way to add performance to a Keihin FCR carburetorIntegrated Hot Start Assist eliminates problem 4-stroke hot start procedureTunable leak jet maximizes volume of fuel and duration of fuel spray for all conditions25% more fuel capacityHigh-volume vertical check valve located in the QS3 for precise, consistent fuel meteringPatented design stops bogging and improves throttle responseImproved low-end performanceInvestment cast and finished to precise tolerancesFits ALL Keihin FCR carbsSimple bolt-on installation