The Harley-Davidson factory warranty is 24 months, unlimited miles, and initiates upon the purchase date and delivery OR 2 years after the Model Year launch. It requires the owner to keep up with their Harley-Davidson maintenance schedule at the prescribed mileage intervals.
It’s a good idea to keep your receipts for any parts, service and maintenance performed on your Harley so that you can transfer to a new owner in the future. If you are regularly servicing your bike at your dealership, then they are keeping records of your bike for you. The warranty is only for Harley-Davidson manufactured parts, so be wary of installing parts from other manufacturers and always check with your authorized dealer before you do.
For full details on the warranty, exclusions and how to obtain warranty service, refer to your owner's manual.