The replacement interval for the chain and sprocket of a Royal Enfield Classic 350 can vary depending on various factors such as riding conditions, maintenance practices, and the quality of the components used. Generally, it is recommended to inspect the chain and sprocket regularly and replace them when signs of wear or damage are evident.
As a guideline, chains on motorcycles typically last between 15,000 to 20,000 kilometers (9,300 to 12,400 miles) under normal riding conditions. However, it's important to note that this can vary and some riders may need to replace their chains and sprockets sooner or later depending on their specific circumstances.
Regular maintenance, including proper lubrication and tension adjustment, can help prolong the life of the chain and sprocket. It's advisable to refer to the owner's manual of the Royal Enfield Classic 350 for the manufacturer's recommendations on chain and sprocket maintenance and replacement intervals specific to your motorcycle model.