The item "Small drive sprocket 428 - 14" is a drive sprocket for Alpha and Delta mopeds. The sprocket transmits rotation to or from the chain. The numbers in the name indicate the chain pitch and the number of teeth.
Replacement is needed if the teeth are worn ("hooked"), the chain is stretched, or there is runout. Replace the sprocket together with the chain. Designation 428-14: chain pitch 428, 14 teeth. Install the part with clean mating surfaces and, where possible, with new gaskets and fasteners.
