If you mean what is JKD's weakness? Well it shouldn't have any because you are trying to adapt to your oponents movements. It's more of a concept so therefore your really just taking the basic structure of JKD and adding and subtracting what works/doesn't work for you. 
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"The art of Jeet Kune Do is simply to simplify. Jeet Kune Do avoids the superficial, penetrates the complex, goes to the heart of the problem and pinpoints the key factors. Empty your cup that it may be filled; become devoid to gain totality." - Sifu Bruce Lee |