What are you trying to balance in your life right now? Career and family? Your emotional balance?
If you’re riding the motorcycle smoothly then your dream is showing you that you’ve got control in reaching your personal and/or professional goals. If you can’t control the motorcycle or a motorcycle is threatening you in any way then your dream is showing you that you don’t have a handle on things right now.
Less often a motorcycle is connected to your need for freedom from a relationship, job or other situation.