Please put the model you have in your signature so we know exactly what you have. Cfmoto has a few different 500's and they are different. As to the stall, I am thinking you bumped off the kill switch or the wire or harness to one of the switches is loose. Bad switch maybe. Does it turn over fine? Does it even try to start? If you have a spark tester, you could just put it on real quick and check. They are cheap if you don't.