My 2003 Katana 600 Will start and run for about ten to twenty seconds then shuts off kind of like it runs out of fuel but it don't spit and sputtered it just shuts down. I have loosened bowl screws while its running and there is fuel there. The bike has set in storage for six years because of it. I got it out yesterday and started tinkering with it again and same thing. Does anyone know an answer for me.