The compatibility of chain sprockets between different motorcycle models can vary, even within the same brand. While the Yamaha R15 and Yamaha FZ16 are both Yamaha motorcycles, it does not necessarily mean that their chain sprockets are interchangeable.
To determine whether the R15's chain sprocket will suit the FZ16, it's best to consult the manufacturer's specifications or reach out to a Yamaha dealership or authorized service center. They will have the most accurate and up-to-date information regarding compatibility between different models and their respective parts. Providing them with the specific details of both motorcycles will help them give you a definitive answer.