From the FAQ:
Q: What happens if my bike breaks down?
A: Each route will have a chase vehicle that is capable of picking up bikes with mechanical issues. The support vehicles will be following the Fully-Guided registrants, and they’re paying more for that service. That said, at heart we’re motorcyclists…so of course, we’ll stop and help you if we see you, no matter how you registered, but if you’re off the Fully-Guided route and/or we’ve passed you, you may need to call a tow service. We’ll get you and your motorcycle to that night’s hotel or to a dealer if there’s one close by and it works within the confines of the event. We’re suggesting that all riders make sure they have some type of roadside assistance before starting the ride with us, and If you are an AMA member, you get free towing with your membership. Many clubs offer this fine service as part of their features and benefits, so check with them to see if you’re covered. Many motorcycle rental companies also have similar programs built into their rental program.