Just buy a Mexico-specific policy from a company like Mexadventure
Your US policy, limited or not, is useless in Mexico anyways, from the standpoint of its validity in the eyes of their legal system.
From the standpoint of damage to your bike or total loss, US policies may or may not apply, depending upon how they're worded.
A Mexico specific policy will cover you under Mexico's Napoleonic Code style rule of law. In other words, you run over a kid in Guadalajara, your US policy is useless. A Mexico specific policy will bond you out of jail and provide you with an English speaking lawyer. Try to show the officiales your US policy, and you will languish in jail until the process runs its course.