Harley Davidson motorcycles typically require the compression release button to be depressed when starting the engine. This is a safety feature designed to ensure proper starting and reduce stress on the starter motor. If you try to start a Harley Davidson motorcycle without depressing the compression release button (if equipped), it may not start or it could potentially cause damage to the starter system.
If you're experiencing difficulties starting your Harley Davidson motorcycle even when following the correct procedure, it's recommended to consult the owner's manual or contact a certified Harley Davidson dealer for assistance. They can provide specific guidance and troubleshoot any issues you may be facing.