My ZZR600e6- similar problem twice for 2 diff reasons. 1- kill switch notorious problem on these bikes, split switch gear spray with contact cleaner and leave to dry, don't have to disassemble totally spray works its way in and evaporates 'WD40 electric contact spray worked for me. 2- same occurred year later battery terminals wire brushed and greased cured it. Good tip when testing charge circuit test battery terminals and test battery posts and between + and engine, frame and starter body. ZZR's notorious for kill switch- rare as rockin horse shit, tried e-bay for ages, no chance. Luck Matey